Patent ID: 12199563

Attachment marks:1. shutdown power line;101. shutdown positive pole line;102. shutdown negative pole line;2. signal receiving module;201. first capacitor;202. second capacitor;203. first inductor;3. signal processing module;301. signal modulation unit;302. threshold comparison unit;303. amplification unit;304. time delay unit;4. controllable switch module;401. driving unit;402. controllable switch;5. linear power module;6. first resistor;7. bypass diode;8. positive bus;9. negative bus;10. inverter;11. controlling signal generator;12. photovoltaic module;13. photovoltaic shutdown.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments and drawings are given below to further illustrate the implementations of the present disclosure. It is to be understood that the embodiments described herein are merely illustrative of the present disclosure and are not intended to be limiting.

As shown inFIG.1, disclosed is a photovoltaic shutdown circuit, which comprises a shutdown power line1, a signal receiving module2, a signal processing module3, and a controllable switch module4. The signal processing module3comprises a signal modulation unit301and a threshold comparison unit302.

A switch end of the controllable switch module4is connected in series to the shutdown power line1to control an on/off of the shutdown power line1.

The signal receiving module2is connected to the shutdown power line1for receiving a first signal with a controlling signal in the shutter power line1; and an output end of the signal receiving module2is connected to the signal processing module3for coupling the first signal into the signal modulation unit301.

The signal modulation unit301is configured to revert the controlling signal of the first signal; and an input end of the threshold comparison unit302is connected to an output end of the signal modulation unit301to receive the reverted controlling signal and compare the reverted controlling signal with a set threshold to output a driving signal.

The controllable switch module4is connected to the threshold comparison unit302to receive the driving signal and control an on/off of the controllable switch module4according to the driving signal.

In use, the photovoltaic shutdown circuit is for connecting a photovoltaic module12and an inverter10; a controlling signal generator11is provided on a bus between the photovoltaic shutdown circuit and the inverter10, and the controlling signal generator11sends a controlling signal to the photovoltaic shutdown circuit through the bus.

By adopting above structure, after the controlling signal generator11sends a controlling signal to the photovoltaic shutdown circuit through the bus, the controlling signal is output to the shutdown power line1, and during the transmission of the controlling signal there will be interference from ripples generated by other electronic components. The signal receiving module2is for receiving the first signal in the shutdown power line1, wherein the first signal comprises the controlling signal and the interference signal. The signal modulation unit301receives the first signal and then reverts the controlling signal, the threshold comparison unit302compares the controlling signal with a set threshold according to the reverted controlling signal to control the controllable switch module4to realize an on/off between the photovoltaic module12and the inverter10.

The above structure can make the photovoltaic shutdown circuit correctly identify the controlling signal from the controlling signal generator which is more than 300 meters away from the photovoltaic shutdown circuit, and can effectively avoid the influence of the interference signal on the control of the photovoltaic shutdown circuit, which can guarantee the stable and reliable operation of the photovoltaic shutdown circuit.

Further, the shutdown power line1comprises a shutdown positive pole line101and a shutdown negative pole line102, and the shutdown negative pole line102is grounded. A switch end of the controllable switch module4is connected in series to the shutdown negative pole line102to control an on/off of the shutdown negative pole line102; the signal processing module3is provided between the shutdown positive pole line101and the shutdown negative pole line102.

Further, the signal processing module3comprises an amplification unit303for amplifying signals, and the output end of the signal modulation unit301is connected to the threshold comparison unit302through the amplification unit303.

By adopting above structure, a controlling signal reverted by the signal modulation unit301is amplified by the amplification unit303and output to the threshold comparison unit302, which enables the threshold comparison unit302to better identify the controlling signal after reduction.

Further, the signal processing module3comprises a time delay unit304for delaying signals, and the threshold comparison unit302is connected to the controllable switch module4through the time delay unit304;

By adopting above structure, the time delay unit304can delay a driving signal output from the threshold comparison unit302to shield a pulse interference signal during a cycle. At the same time, the time delay unit304can accelerate a function of shutting off the controllable switch module4to prevent frequent switching of the controllable switch module4caused by weakening of the photovoltaic module in early morning and at night, or to prevent the occurrence of serious heating of the controllable switch module4caused by starting fast shutdown function under high current or instant short circuit, or to prevent the occurrence of breakthrough damage.

The time delay unit304provides an input signal 20 milliseconds to 500 milliseconds delay.

The aforementioned photovoltaic shutdown circuit further comprises a linear power module5, an input end of the linear power module5is connected to the shutdown power line1, and an output end of the linear power module5is connected to the signal processing module3and/or the controllable switch module4to supply power to the signal processing module3and the controllable switch module4. The input end of the linear power module5is connected to the shutdown positive pole line101.

The above structure can guarantee the stability of the operation of the photovoltaic shutdown circuit.

Further, the input end of the linear power module5is connected to the shutdown positive pole line101through a first resistor6.

By adopting above structure, the first resistor6is able to absorb the controlling signal with damping; a resistance value of the first resistor6is in a range of from 2.2Ω to 499Ω.

Further, the signal receiving module2comprises a first capacitor201, a second capacitor202, and a first inductor203. One end of the first capacitor201is connected to the shutdown negative pole line102and another end of the first capacitor201is connected to one end of the first inductor203, and another end of the first inductor203is connected to one end of the second capacitor202, and another end of the second capacitor202is connected to the shutdown positive pole line101, and the end of the first capacitor201connected to one end of the first inductor203is grounded, and the end of the second capacitor202connected to one end of the first inductor203is formed to be the output end of the signal receiving module2.

By adopting above structure, the first signal in the shutdown power line1is coupled into the signal modulation unit301after a coupling of the first capacitor201and a resonant frequency selection by the first inductor203and second capacitor202.

Further, the signal modulation unit301adopts a bandstop filter.

By adopting above structure, the bandstop filter attenuates the first signal and then reverts the control signal to reach the modulation purpose of attenuating a high frequency ripple signal to revert the control signal.

Further, the threshold comparison unit302adopts a threshold comparator, and a threshold voltage of the threshold comparator is in a range of 0.1 V to 12 V.

Further, the amplification unit303adopts an operational amplifier.

Further, the controllable switch module4comprises a controllable switch402that has a controlling end and a switch end, and a driving unit401that drives an on/off of the controllable switch402. An input end of the driving unit401is connected to the threshold comparison unit302, an output end of the driving unit401is connected to the controlling end of the controllable switch402.

Further, the controllable switch402comprises a MOS transistor, a drain and a source of the MOS transistor are formed to be a switch end of the controllable switch402, and a gate of the MOS transistor is formed to be a controlling end of the controllable switch402.

The photovoltaic shutdown circuit further comprises a bypass diode7, a positive pole of the bypass diode7is connected to the shutdown negative pole line102, and a negative pole of the bypass diode7is connected to the shutdown positive pole line101.

As shown inFIGS.1and2, a photovoltaic system, comprising a positive bus8, a negative bus9, an inverter10, a controlling signal generator11, N photovoltaic modules12, and N photovoltaic shutdowns13is disclosed. N is a positive integer, and the photovoltaic shutdown13comprises the photovoltaic shutdown circuit described above.

One end of the shutdown power line1is formed to be an output end of the photovoltaic shutdown circuit and another end of the shutdown power line1is formed to be an input end of the photovoltaic shutdown circuit.

The output ends of the photovoltaic shutdown circuits are connected in series, and a positive pole of the output ends of the photovoltaic shutdown circuits connected in series is connected to the positive bus8, and a negative pole of the output ends of the photovoltaic shutdown circuits connected in series is connected to the negative bus9.

The input ends of the photovoltaic shutdown circuit are respectively and correspondently connected to each photovoltaic module12one to one.

The positive bus8is connected to a positive pole on a DC side of the inverter10, and the negative bus9is connected to the negative pole on the DC side of the inverter10. The controlling signal generator11is connected to the negative bus8to output controlling signals.

It is to be understood that the present disclosure is not limited to the embodiments described above. Modifications and variations may be resorted to in light of the above teachings by those skilled in the art, all these modifications and variations should be considered as falling within the scope of the appended claims.