Safety protection circuit for inverter patch cord interface

Abstract

The utility model provides a safety protection circuit for an inverter patch cord interface, which 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. According to the circuit provided by the utility model, the ripple of the 12V interface 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, a charging pile and the like through the patch cord.

Description

Technical Field

[0001] This utility model is applied to the field of distributed photovoltaic access, and in particular relates to the access protection circuit of the distributed photovoltaic access unit interface connected to the inverter, energy storage PCS and charging pile through the adapter cable. Background Technology

[0002] With the rapid development of clean energy, distributed power generation access systems, as an important component of smart grids, have seen their security and reliability become a 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 the adapter cable. Therefore, the security and reliability of the interface protection needs to be addressed. Summary of the Invention

[0004] This utility model provides a safety protection circuit for inverter adapter interfaces, aiming to solve the safety and reliability problems in the process of distributed power supply access.

[0005] The technical solution of this utility model is:

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

[0007] The output voltage of the transformer is connected to the input terminal of the primary power supply filter circuit B via the absorption circuit A; the output terminal of the primary power supply filter circuit B is connected to the input terminal of the overcurrent protection circuit C; and the output terminal of the overcurrent protection circuit C is connected to the input terminal of the interface 12V filter circuit D.

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

[0009] The positive terminal of diode D1 and one end of resistor R1 are connected in parallel as the input of absorption circuit A and connected to the output of transformer. The other end of resistor R1 is connected to one end of capacitor C1, and the other end of capacitor C1 is connected to the negative terminal of diode D1. The connection point serves as the output of absorption circuit A and is connected to the input of filter circuit B. Resistor R1 and capacitor C1 constitute an RC absorption circuit, which is used to absorb harmonics and noise of switching signals.

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

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

[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, Zener diode D2, and LED.

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

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

[0016] Furthermore, the interface 12V filter circuit D includes capacitors C7-C11 and inductor L2;

[0017] The capacitors C8 and C9, together with the inductor L2, form a π-type filter circuit, which is then connected in parallel to ground with capacitors C7, C10, and C11.

[0018] Furthermore, capacitor C7 is an electrolytic capacitor, and the value of capacitor C10 is 100 times that of capacitor C11.

[0019] The beneficial effects of this utility model are:

[0020] This utility model provides a safety protection circuit that not only achieves very low ripple at the 12V interface, but also provides safety protection for the 12V interface when a short circuit occurs at the inverter adapter cable interface. This protects the safety of downstream devices connected to the 12V interface via the adapter cable, and enables safe and reliable connection to photovoltaic inverters, energy storage PCS, and charging piles via the adapter cable.

[0021] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0022] The above and other objects, features and advantages of the present invention will become more apparent from the accompanying drawings, in which like reference numerals generally represent like parts.

[0023] Figure 1 This is a structural diagram of the present invention. Detailed Implementation

[0024] Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. Although preferred embodiments of the present invention are shown in the 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.

[0025] like Figure 1 As shown, this utility model provides a safety protection circuit for an inverter adapter interface, including an absorption circuit A, a primary power supply filter circuit B, an overcurrent protection circuit C, and an interface 12V filter circuit D connected in sequence. The output voltage of the transformer is connected to the input terminal of the primary power supply filter circuit B via the output of the absorption circuit A; the output terminal of the primary power supply filter circuit B is connected to the input terminal of the overcurrent protection circuit C; the output terminal of the overcurrent protection circuit C is connected to the input terminal of the interface 12V filter circuit D. After filtering by the interface filter circuit, the 12V ripple can reach 1‰.

[0026] The absorption circuit A includes a diode D1, a resistor R1, and a capacitor C1. The positive terminal 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 terminal of the diode D1. The connection point serves as the output of the absorption circuit A and is connected to the input of the filter circuit B. The resistor R1 and the capacitor C1 constitute an RC absorption circuit, which is used to absorb harmonics and noise of the switching signal.

[0027] The primary filter circuit B of the power supply includes electrolytic capacitors C2 and C3, capacitors C4 and C5, and inductor L1;

[0028] The electrolytic capacitors C2 and C3, together with the inductor L1, form a π-type filter circuit, which is then connected to ground in parallel with capacitors C4 and C5; the value of capacitor C4 is one hundred times that of C5.

[0029] For example, electrolytic capacitors C2 and C3 are 470uF, C4 and C5 are 100nF and 1nF respectively; inductor L1 is 10uH to form a π-type filter, which together with two small capacitors C4 and C5 in a ratio of hundreds to form the primary filter circuit of the power supply.

[0030] The overcurrent protection circuit C includes transistors Q1-Q4, resistors R3-R9, capacitor C6, Zener diode D2, and LED. Q1 is a TIP42C PNP power transistor with a collector-emitter saturation voltage of 1.5 V and a maximum collector current of 6 A. Q3 and Q4 are 9014 NPN power transistors, Q2 is a 9102 PNP power transistor, and R6 has a small resistance of 100Ω.

[0031] The emitter of transistor Q1 serves as the input of the overcurrent protection circuit C, connected to the output of the power supply output filter circuit B, and is also connected to one end of resistors R3 and R4, and the emitter of transistor Q2. The base of transistor Q1 is connected to the collector of transistor Q3. The collector of transistor Q1 is connected to one end of resistor R5 and capacitor C6, and the connection point serves as the output of the overcurrent protection circuit C. The other end of capacitor C6 is connected to the other end of resistor R3. The base of transistor Q2 is connected to the LED, Zener diode D2, and resistor R5. The emitter of transistor Q2 is connected to resistor R6 and the base of transistor Q4. The base of transistor Q3 is connected to resistor R8 and one end of capacitor C6. The other end of resistor R8 is connected to resistor R9 and the collector of transistor Q4. The emitter of transistor Q3 is connected in series with resistor R7 and then grounded. The emitter of transistor Q4 is grounded.

[0032] During normal operation, the overcurrent protection circuit C performs the following steps:

[0033] The voltage output from the primary power supply filter circuit B charges capacitor C6 after passing through resistors R3, R8, and R9. The voltage formed by the charging of capacitor C6 is applied to the base of transistor Q3, turning on transistor Q3. This forms a loop with resistor R7 and ground, causing the base of transistor Q1 to go low. Then, transistor Q1 saturates and turns on. At this point, the voltage output from the primary power supply filter circuit B is normally output through transistor Q1.

[0034] When a short circuit occurs in the load of the 12V output interface, the overcurrent protection circuit C performs the following steps:

[0035] The voltage between a and b, i.e., the voltage between the emitter and collector of transistor Q1, is greater than the sum of the LED's turn-on voltage and the Zener diode D2's breakdown voltage.

[0036] The voltage output after filtering by the primary filter circuit B of the power supply forms a loop with resistor R4, LED, Zener diode D2, resistor R5 and ground, making the base of transistor Q2 low level, and thus transistor Q2 conducts.

[0037] The voltage output from the primary filter circuit B of the power supply is output to the transistor Q4 through resistor R6. When the base of transistor Q4 becomes high, transistor Q4 is turned on.

[0038] The voltage output from the primary power supply filter circuit B forms a loop with transistor Q2, resistor R6, the base and emitter of transistor Q4, and ground. This causes the collector of transistor Q4 to go low, simultaneously pulling down the base of transistor Q3, preventing Q3 from conducting. Consequently, the base of transistor Q1 cannot form a low level, and Q1 cannot conduct. Therefore, the power supply filtered by the primary power supply filter circuit B cannot output power, thus protecting the power supply circuit from overcurrent and ensuring the safety of the 12V interface.

[0039] The 12V interface filter circuit D includes capacitors C7-C11 and inductor L2. Capacitors C8 and C9, along with inductor L2, form a π-type filter circuit, which is then connected to ground in parallel with capacitors C7, C10, and C11. C8 and C9 are 10uF capacitors, forming a π-type filter with the 3.3uH inductor L2. In addition, a 470uF electrolytic capacitor C7 and two small capacitors C10 and C11, which are proportionally many times larger, form the 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, and charging piles through adapter cables.

[0040] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations 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 primary power supply 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 terminal of the primary power supply filter circuit B via the output of the absorption circuit A; the output terminal of the primary power supply filter circuit B is connected to the input terminal of the overcurrent protection circuit C; and the output terminal of the overcurrent protection circuit C is connected to the input terminal of the interface 12V filter circuit D.

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

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

4. The safety protection circuit for the inverter adapter interface according to claim 3, characterized in that... The value of capacitor C4 is 100 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, Zener diode D2, and LED. The emitter of transistor Q1 serves as the input of the overcurrent protection circuit C, connected to the output of the power supply output filter circuit B, and is also connected to one end of resistors R3 and R4, and the emitter of transistor Q2. The base of transistor Q1 is connected to the collector of transistor Q3. The collector of transistor Q1 is connected to one end of resistor R5 and capacitor C6, and the connection point serves as the output of the overcurrent protection circuit C. The other end of capacitor C6 is connected to the other end of resistor R3. The base of transistor Q2 is connected to the LED, Zener diode D2, and resistor R5. The emitter of transistor Q2 is connected to resistor R6 and the base of transistor Q4. The base of transistor Q3 is connected to resistor R8 and one end of capacitor C6. The other end of resistor R8 is connected to resistor R9 and the collector of transistor Q4. The emitter of transistor Q3 is connected in series with resistor R7 and then grounded. The emitter of transistor Q4 is grounded.

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

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

8. The safety protection circuit for the inverter adapter interface according to claim 7, characterized in that... Capacitor C7 is an electrolytic capacitor, and the value of capacitor C10 is 100 times that of capacitor C11.

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