Safety protection circuit for inverter patch cord interface

Abstract

The invention provides a safety protection circuit for an inverter patch cord interface. The safety protection circuit comprises an absorption circuit A, a power supply primary filter circuit B, an overcurrent protection circuit C and an interface 12V filter circuit D. The output voltage of a transformer is connected with the input end of the power supply primary filter circuit B through the output of the absorption circuit A; the output end of the power supply primary filter circuit B is connected with the input end of the overcurrent protection circuit C; and the output end of the overcurrent protection circuit C is connected with the input end of the interface 12V filter circuit D, and 12V ripples can reach 0.1% after the 12V ripples are filtered by the interface filter circuit. According to the circuit provided by the invention, the 12V interface ripple is very small, the 12V interface can be safely protected when the 12V interface of the inverter patch cord is short-circuited, the safety of equipment which is accessed to the 12V interface through the patch cord is protected, and the 12V interface can be safely and reliably accessed to equipment such as a photovoltaic inverter, an energy storage PCS and a charging pile through the patch cord.

Description

Technical Field

[0001] The present invention is applied to the field of distributed photovoltaic access, and in particular relates to an access protection circuit for a distributed photovoltaic access unit interface to access an inverter, an energy storage PCS and a charging pile through a switching line. Background Art

[0002] With the rapid development of clean energy, the security and reliability of distributed power access systems, as an important part of smart grids, have become the focus of attention.

[0003] The interface of the distributed power access unit needs to be connected to the inverter, energy storage PCS and charging pile through a adapter cable, so the safety and reliability issues of interface protection need to be urgently addressed. Summary of the invention

[0004] The present invention provides a safety protection circuit for an inverter adapter interface, aiming to solve the safety and reliability problems in the process of distributed power supply access.

[0005] The technical solution of the present invention is:

[0006] A safety protection circuit for an inverter adapter interface comprises an absorption circuit A, a power supply primary filter circuit B, an overcurrent protection circuit C and an interface 12V filter circuit D connected in sequence, wherein:

[0007] The output voltage of the transformer is connected to the input end of the primary filter circuit B of the power supply via the output of the absorption circuit A; the output end of the primary filter circuit B of the power supply is connected to the input end of the overcurrent protection circuit C; the output end of the overcurrent protection circuit C is connected to the input end of the interface 12V filter circuit D. After filtering by the interface filter circuit, the 12V ripple can reach 1‰.

[0008] Further, the absorption circuit A includes a diode D1, a resistor R1 and a capacitor C1;

[0009] The positive electrode of the diode D1 and one end of the resistor R1 are connected in parallel as the input of the absorption circuit A and connected to the output of the transformer. The other end of the resistor R1 is connected to one end of the capacitor C1. The other end of the capacitor C1 is connected to the negative electrode of the diode D1. The connection point is connected to the input of the filter circuit B as the output of the absorption circuit A. The resistor R1 and the capacitor C1 constitute an RC absorption circuit for absorbing harmonics and noise of the switching signal.

[0010] Further, the power supply primary filter circuit B includes electrolytic capacitors C2, C3, capacitors C4, C5 and inductor L1;

[0011] The electrolytic capacitors C2 and C3 and the inductor L1 form a π-type filter circuit, which is then connected to the ground in parallel with the capacitors C4 and C5.

[0012] Furthermore, the value of capacitor C4 is one hundred times that of C5.

[0013] Furthermore, the overcurrent protection circuit C includes transistors Q1-Q4, resistors R3-R9, capacitor C6, voltage regulator D2 and LED lamp;

[0014] The emitter of the transistor Q1 is connected to the output of the power supply output filter circuit B as the input of the overcurrent protection circuit C, and is connected to one end of the resistors R3 and R4 and the emitter of the transistor Q2. The base of the transistor Q1 is connected to the collector of the transistor Q3. The collector of the transistor Q1 is connected to the resistor R5 and one end of the capacitor C6, and the connection point serves as the output of the overcurrent protection circuit C. The other end of the capacitor C6 is connected to the other end of the resistor R3. The base of the transistor Q2 is connected to the LED lamp, the voltage regulator D2 and the resistor R5. The emitter of the transistor Q2 is connected to the resistor R6 and the base of the transistor Q4. The base of the transistor Q3 is connected to the resistor R8 and one end of the capacitor C6. The other end of the resistor R8 is connected to the resistor R9 and the collector of the transistor Q4. The emitter of the transistor Q3 is connected in series with the resistor R7 and then grounded. The emitter of the transistor Q4 is grounded.

[0015] Furthermore, the transistors Q1 and Q2 are PNP power transistors, and the transistors Q3 and Q4 are NPN power transistors.

[0016] Furthermore, during normal operation, the overcurrent protection circuit C performs the following steps:

[0017] The voltage output by the primary filter circuit B of the power supply charges the capacitor C6 after passing through the resistors R3, R8 and R9. The voltage formed after the capacitor C6 is charged is added to the base of the transistor Q3. The transistor Q3 is turned on, and a loop is formed with the resistor R7 and the ground, so that the base of the transistor Q1 becomes a low level, and then the transistor Q1 is saturated and turned on; at this time, the voltage output by the primary filter circuit B of the power supply after filtering is normally output through the transistor Q1.

[0018] Furthermore, when the 12V output interface load is short-circuited, the overcurrent protection circuit C performs the following steps:

[0019] The voltage between a and b, that is, the voltage between the emitter and collector of transistor Q1, is greater than the sum of the conduction voltage of the LED lamp and the breakdown voltage of the voltage regulator D2;

[0020] The output voltage after filtering by the primary filter circuit B of the power supply forms a loop with the resistor R4, the LED lamp, the voltage regulator D2, the resistor R5 and the ground, so that the base of the transistor Q2 is at a low level, and the transistor Q2 is turned on;

[0021] The voltage outputted by the primary filter circuit B of the power supply after filtering is outputted to the transistor Q4 through the resistor R6, and the base of the transistor Q4 becomes a high level, and the transistor Q4 is turned on;

[0022] The voltage output after filtering by the primary filter circuit B of the power supply forms a loop with the transistor Q2, resistor R6, the base and emitter of the transistor Q4 and the ground, so that the collector of the transistor Q4 becomes a low level, and at the same time, the base of the transistor Q3 is pulled down to a low level, so that the transistor Q3 cannot be turned on, and the base of the transistor Q1 cannot form a low level, the transistor Q1 cannot be turned on, and the power after filtering by the primary filter circuit B of the power supply cannot be output, so the power supply circuit is protected from overcurrent and the safety of the 12V interface is protected.

[0023] Further, the interface 12V filter circuit D includes capacitors C7-C11 and inductor L2;

[0024] The capacitors C8 and C9 and the inductor L2 form a π-type filter circuit, which is then connected to the ground in parallel with the capacitors C7, C10, and C11.

[0025] Furthermore, capacitor C7 is an electrolytic capacitor, and the value of capacitor C10 is one hundred times that of capacitor C11.

[0026] The beneficial effects of the present invention are:

[0027] The present invention provides a safety protection circuit, which not only realizes that the ripple of the 12V interface is very small, but also can play a safety protection effect on the 12V interface when a short circuit occurs in the 12V of the inverter adapter line interface, thereby protecting the safety of the subsequent equipment connected to the 12V interface through the adapter line, and can safely and reliably connect to equipment such as photovoltaic inverters, energy storage PCS and charging piles through the adapter line.

[0028] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0030] Figure 1 It is a structural diagram of the present invention. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0032] like Figure 1As shown, the present invention provides a safety protection circuit for an inverter adapter interface, comprising an absorption circuit A, a power supply primary filter circuit B, an overcurrent protection circuit C and an interface 12V filter circuit D connected in sequence, wherein the output voltage of the transformer is connected to the input end of the power supply primary filter circuit B via the output of the absorption circuit A; the output end of the power supply primary filter circuit B is connected to the input end of the overcurrent protection circuit C; the output end of the overcurrent protection circuit C is connected to the input end of the interface 12V filter circuit D, and after filtering by the interface filter circuit, the 12V ripple can reach 1‰.

[0033] The absorption circuit A includes a diode D1, a resistor R1 and a capacitor C1; the positive electrode of the diode D1 and one end of the resistor R1 are connected in parallel as the input of the absorption circuit A and connected to the output of the transformer, the other end of the resistor R1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to the negative electrode of the diode D1. The connection point is connected to the input of the filter circuit B as the output of the absorption circuit A. The resistor R1 and the capacitor C1 constitute an RC absorption circuit for absorbing harmonics and noise of the switching signal.

[0034] The power supply primary filter circuit B includes electrolytic capacitors C2, C3, capacitors C4, C5 and inductor L1;

[0035] The electrolytic capacitors C2, C3 and the inductor L1 form a π-type filter circuit, which is then connected to the ground in parallel with the capacitors C4 and C5; the value of the capacitor C4 is one hundred times that of C5.

[0036] For example, the electrolytic capacitors C2 and C3 are 470uF, C4 and C5 are 100nF and 1nF respectively; the inductor L1 is 10uH to form a π-type filter, and then together with two small capacitors C4 and C5 with a hundred times the ratio, form a primary filter circuit of the power supply.

[0037] The overcurrent protection circuit C includes transistors Q1-Q4, resistors R3-R9, capacitor C6, voltage regulator D2 and LED lamp. Q1 is a TIP42C PNP power transistor with a collector-emitter saturation voltage of 1.5V and a maximum collector current of 6A. Q3 and Q4 are 9014NPN power transistors, Q2 is a 9102PNP power transistor, and R6 has a relatively small resistance of 100Ω.

[0038] The emitter of the transistor Q1 is connected to the output of the power supply output filter circuit B as the input of the overcurrent protection circuit C, and is connected to one end of the resistors R3 and R4 and the emitter of the transistor Q2. The base of the transistor Q1 is connected to the collector of the transistor Q3. The collector of the transistor Q1 is connected to the resistor R5 and one end of the capacitor C6, and the connection point serves as the output of the overcurrent protection circuit C. The other end of the capacitor C6 is connected to the other end of the resistor R3. The base of the transistor Q2 is connected to the LED lamp, the voltage regulator D2 and the resistor R5. The emitter of the transistor Q2 is connected to the resistor R6 and the base of the transistor Q4. The base of the transistor Q3 is connected to the resistor R8 and one end of the capacitor C6. The other end of the resistor R8 is connected to the resistor R9 and the collector of the transistor Q4. The emitter of the transistor Q3 is connected in series with the resistor R7 and then grounded. The emitter of the transistor Q4 is grounded.

[0039] During normal operation, the overcurrent protection circuit C performs the following steps:

[0040] The voltage output by the primary filter circuit B of the power supply charges the capacitor C6 after passing through the resistors R3, R8 and R9. The voltage formed after the capacitor C6 is charged is added to the base of the transistor Q3. The transistor Q3 is turned on, and a loop is formed with the resistor R7 and the ground, so that the base of the transistor Q1 becomes a low level, and then the transistor Q1 is saturated and turned on; at this time, the voltage output by the primary filter circuit B of the power supply after filtering is normally output through the transistor Q1.

[0041] When the 12V output interface load is short-circuited, the overcurrent protection circuit C performs the following steps:

[0042] The voltage between a and b, that is, the voltage between the emitter and collector of transistor Q1, is greater than the sum of the conduction voltage of the LED lamp and the breakdown voltage of the voltage regulator D2;

[0043] The output voltage after filtering by the primary filter circuit B of the power supply forms a loop with the resistor R4, the LED lamp, the voltage regulator D2, the resistor R5 and the ground, so that the base of the transistor Q2 is at a low level, and the transistor Q2 is turned on;

[0044] The voltage outputted by the primary filter circuit B of the power supply after filtering is outputted to the transistor Q4 through the resistor R6, and the base of the transistor Q4 becomes a high level, and the transistor Q4 is turned on;

[0045] The voltage output after filtering by the primary filter circuit B of the power supply forms a loop with the transistor Q2, resistor R6, the base and emitter of the transistor Q4 and the ground, so that the collector of the transistor Q4 becomes a low level, and at the same time, the base of the transistor Q3 is pulled down to a low level, so that the transistor Q3 cannot be turned on, and the base of the transistor Q1 cannot form a low level, the transistor Q1 cannot be turned on, and the power after filtering by the primary filter circuit B of the power supply cannot be output, so the power supply circuit is protected from overcurrent and the safety of the 12V interface is protected.

[0046] The interface 12V filter circuit D includes capacitors C7-C11 and inductor L2; the capacitors C8, C9 and inductor L2 form a π-type filter circuit, which is then connected to the ground in parallel with capacitors C7, C10 and C11. C8 and C9 are 10uF capacitors, which form a π-type filter with the 3.3uH inductor L2, and a 470uF electrolytic capacitor C7 and two small capacitors C10 and C11 with a hundred times the ratio form a 12V interface filter circuit. C10 and C11 are 100nF and 1uF respectively. After testing, the 12V interface ripple can reach 1‰ of 12V, which can provide a more stable 12V output and can be safely and reliably connected to photovoltaic inverters, energy storage PCS, charging piles and other equipment through adapters.

[0047] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A safety protection circuit for an inverter adapter interface, characterized in that: It includes an absorption circuit A, a power supply primary filter circuit B, an overcurrent protection circuit C and an interface 12V filter circuit D connected in sequence, wherein: The output voltage of the transformer is connected to the input end of the primary filter circuit B of the power supply via the output of the absorption circuit A; the output end of the primary filter circuit B of the power supply is connected to the input end of the overcurrent protection circuit C; the output end of the overcurrent protection circuit C is connected to the input end of the interface 12V filter circuit D. After filtering by the interface filter circuit, the 12V ripple can reach 1‰.

2. The safety protection circuit for the inverter adapter interface according to claim 1, characterized in that The absorption circuit A comprises a diode D1, a resistor R1 and a capacitor C1; The positive electrode of the diode D1 and one end of the resistor R1 are connected in parallel as the input of the absorption circuit A and connected to the output of the transformer. The other end of the resistor R1 is connected to one end of the capacitor C1. The other end of the capacitor C1 is connected to the negative electrode of the diode D1. The connection point is connected to the input of the filter circuit B as the output of the absorption circuit A. The resistor R1 and the capacitor C1 constitute an RC absorption circuit for absorbing harmonics and noise of the switching signal.

3. The safety protection circuit for the inverter adapter interface according to claim 1, characterized in that The power supply primary filter circuit B includes electrolytic capacitors C2, C3, capacitors C4, C5 and inductor L1; The electrolytic capacitors C2 and C3 and the inductor L1 form a π-type filter circuit, which is then connected to the ground in parallel with the capacitors C4 and C5.

4. The safety protection circuit for the inverter adapter interface according to claim 3 is characterized in that The value of capacitor C4 is one hundred times that of C5.

5. The safety protection circuit for the inverter adapter interface according to claim 1, characterized in that The overcurrent protection circuit C includes transistors Q1-Q4, resistors R3-R9, capacitor C6, voltage regulator D2 and LED lamp; The emitter of the transistor Q1 is connected to the output of the power supply output filter circuit B as the input of the overcurrent protection circuit C, and is connected to one end of the resistors R3 and R4 and the emitter of the transistor Q2. The base of the transistor Q1 is connected to the collector of the transistor Q3. The collector of the transistor Q1 is connected to the resistor R5 and one end of the capacitor C6, and the connection point serves as the output of the overcurrent protection circuit C. The other end of the capacitor C6 is connected to the other end of the resistor R3. The base of the transistor Q2 is connected to the LED lamp, the voltage regulator D2 and the resistor R5. The emitter of the transistor Q2 is connected to the resistor R6 and the base of the transistor Q4. The base of the transistor Q3 is connected to the resistor R8 and one end of the capacitor C6. The other end of the resistor R8 is connected to the resistor R9 and the collector of the transistor Q4. The emitter of the transistor Q3 is connected in series with the resistor R7 and then grounded. The emitter of the transistor Q4 is grounded.

6. The safety protection circuit for the inverter adapter interface according to claim 5, characterized in that The transistors Q1 and Q2 are PNP power transistors, and the transistors Q3 and Q4 are NPN power transistors.

7. The safety protection circuit for the inverter adapter interface according to claim 5, characterized in that During normal operation, the overcurrent protection circuit C performs the following steps: The voltage output by the primary filter circuit B of the power supply charges the capacitor C6 after passing through the resistors R3, R8 and R9. The voltage formed after the capacitor C6 is charged is added to the base of the transistor Q3. The transistor Q3 is turned on, and a loop is formed with the resistor R7 and the ground, so that the base of the transistor Q1 becomes a low level, and then the transistor Q1 is saturated and turned on; at this time, the voltage output by the primary filter circuit B of the power supply after filtering is normally output through the transistor Q1.

8. The safety protection circuit for the inverter adapter interface according to claim 5, characterized in that When the 12V output interface load is short-circuited, the overcurrent protection circuit C performs the following steps: The voltage between a and b, that is, the voltage between the emitter and collector of transistor Q1, is greater than the sum of the conduction voltage of the LED lamp and the breakdown voltage of the voltage regulator D2; The output voltage after filtering by the primary filter circuit B of the power supply forms a loop with the resistor R4, the LED lamp, the voltage regulator D2, the resistor R5 and the ground, so that the base of the transistor Q2 is at a low level, and the transistor Q2 is turned on; The voltage outputted by the primary filter circuit B of the power supply after filtering is outputted to the transistor Q4 through the resistor R6, and the base of the transistor Q4 becomes a high level, and the transistor Q4 is turned on; The voltage output after filtering by the primary filter circuit B of the power supply forms a loop with the transistor Q2, resistor R6, the base and emitter of the transistor Q4 and the ground, so that the collector of the transistor Q4 becomes a low level, and at the same time, the base of the transistor Q3 is pulled down to a low level, so that the transistor Q3 cannot be turned on, and the base of the transistor Q1 cannot form a low level, the transistor Q1 cannot be turned on, and the power after filtering by the primary filter circuit B of the power supply cannot be output, so the power supply circuit is protected from overcurrent and the safety of the 12V interface is protected.

9. The safety protection circuit for the inverter adapter interface according to claim 1, characterized in that The interface 12V filter circuit D includes capacitors C7-C11 and inductor L2; The capacitors C8 and C9 and the inductor L2 form a π-type filter circuit, which is then connected to the ground in parallel with the capacitors C7, C10, and C11.

10. The safety protection circuit for the inverter adapter interface according to claim 9, characterized in that Capacitor C7 is an electrolytic capacitor, and the value of capacitor C10 is one hundred times that of capacitor C11.

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