Power supply protection circuit based on non-intrusive power load monitoring terminal

Abstract

The utility model relates to the technical field of protection circuits, in particular to a power supply protection circuit based on a non-intrusive power load monitoring terminal, which comprises a transformer T1 and a transformer T2 which are connected in series, the transformer T2 is electrically connected with a transformer T3 through a rectification filter, a collector electrode L22 is electrically connected with a diode VD39, and the collector electrode L22 is electrically connected with a diode D1. And one side, far away from the high-power switch tube V3, of the diode VD39 is electrically connected with a constant-current driving tube V20, a high-power switch tube V21, an under-voltage protection control tube V38 and an over-current protection control tube V25. The diode VD39 provides a discharge loop for the positive feedback coupling capacitor C19 to prevent breakdown of b-e poles of the high-power switch tube V3, the constant-current driving tube V20 provides constant-current driving current for the high-power switch tube V3, and the high-power switch tube V22 is conducted after the overcurrent protection control tube V25 is conducted, so that the high-power switch tube V3 is in a cut-off state due to overcurrent.

Description

Technical Field

[0001] The utility model relates to a power supply protection circuit, in particular to a power supply protection circuit based on a non-intrusive power load monitoring terminal, and belongs to the technical field of protection circuits. Background Art

[0002] A protection circuit is a circuit in an electrical device or electronic system designed to prevent unstable factors such as electrical faults, short circuits, overloads, overvoltages, overcurrents, and overheating from affecting the circuit's performance and causing damage to the equipment. The importance of a protection circuit is self-evident. It ensures the safety and reliability of equipment and systems, and avoids equipment damage, system crashes, and even casualties caused by electrical problems.

[0003] Existing circuits often use fuses or some simple circuits to protect downstream devices. Once strong interference occurs, either the fuse will burn out or the device will be powered off. Currently, circuit structures with short-circuit, overload, and overvoltage functions are usually more complex and difficult to repair.

[0004] Therefore, there is an urgent need to improve the power protection circuit of the monitoring terminal to solve the above problems. Utility Model Content

[0005] The purpose of the utility model is to provide a power protection circuit based on a non-intrusive power load monitoring terminal. The diode VD39 provides a discharge circuit for the positive feedback coupling capacitor C19 to prevent the be-pole breakdown of the high-power switch tube V3. The constant current drive tube V20 provides a constant current drive current for the high-power switch tube V3, so that the AC input voltage range of the switching power supply is expanded to 90-270V. The conduction of the high-power switch tube V3 is delayed for a period of time to reduce the power loss generated by the high-power switch tube V3 flipping from the cut-off state to the saturation state. After the overcurrent protection control tube V25 is turned on, the high-power switch tube V22 is turned on, so that the switch tube high-power switch tube V3 is in the cut-off state due to overcurrent.

[0006] In order to achieve the above-mentioned purpose, the main technical solutions adopted by this utility model include:

[0007] A power protection circuit based on a non-intrusive power load monitoring terminal includes a transformer T1 and a transformer T2 connected in series. The transformer T2 is electrically connected to a transformer T3 through rectification and filtering. The terminal pins 1 and 5 of the transformer T3 are electrically connected to a high-power switch tube V3. The transformer T3 is electrically connected to the high-power switch tube V3 through collectors L22 and L23.

[0008] The collector L22 is electrically connected to a diode VD39 , and the side of the diode VD39 away from the high-power switch tube V3 is electrically connected to a constant current drive tube V20 , a high-power switch tube V21 , an undervoltage protection control tube V38 , and an overcurrent protection control tube V25 .

[0009] Preferably, the windings of the terminal pins 7 and 9 of the transformer T3 are positive feedback windings, and the feedback potential thereof is coupled to the base of the high-power switch tube V3 via the resistor R26 and the capacitor C19.

[0010] Preferably, the end pin 8 and the end pin 7 of the transformer T3 are electrically connected to the diode VD20 and the capacitor C21, and are electrically connected to the constant current driving tube V20 through the resistor R22, and the end pin 9 of the transformer T3 is connected to the constant current driving tube V20 through the resistor R23.

[0011] Preferably, the high-power switch tube V21 is electrically connected to a diode VD44 , and the terminal pins 8 and 7 of the transformer T3 are connected to a capacitor C33 via a diode VD43 .

[0012] Preferably, the terminal pins 7 and 9 of the transformer T3 are electrically connected to a capacitor C26 via a diode VD24, and the capacitor C26 is electrically connected to the undervoltage protection control tube V38 via resistors R69 and R67.

[0013] Preferably, the base of the undervoltage protection control tube V38 is electrically connected to the external 300V voltage through the resistor R68.

[0014] Preferably, the undervoltage protection control tube V38 is electrically connected to the high-power switch tube V24 and the high-power switch tube V22.

[0015] Preferably, the high-power switch tube V3 is electrically connected to a resistor R39, the resistor R39 is electrically connected to the base of the overcurrent protection control tube V25 through a resistor R33, and the overcurrent protection control tube V25 is connected to the high-power switch tube V22.

[0016] The utility model has at least the following beneficial effects:

[0017] 1. Diode VD39 provides a discharge circuit for the positive feedback coupling capacitor C19 to prevent the be-pole breakdown of the high-power switch tube V3. The constant current drive tube V20 provides constant current drive current for the high-power switch tube V3, expanding the AC input voltage range of the switching power supply to 90-270V. The turn-on of the high-power switch tube V3 is delayed for a period of time to reduce the power loss generated by the instantaneous transition of the high-power switch tube V3 from the cut-off state to the saturation state. After the overcurrent protection control tube V25 is turned on, the high-power switch tube V22 is turned on, and the switch tube high-power switch tube V3 is turned off due to overcurrent.

[0018] 2. The high-power switch tube V21 has two functions. The first is overvoltage protection. When the voltage across the capacitor C21 rises from the normal value of 8V to 10V, the diode VD44 breaks down and turns on, causing the high-power switch tube V21 to turn on. The base excitation current of the high-power switch tube V3 is short-circuited by the CE electrode of the high-power switch tube V21, causing the high-power switch tube V3 to be in the cut-off state and protected. The second function is to delay the turn-on of the high-power switch tube V3 to reduce the power loss generated by the instantaneous flip of the high-power switch tube V3 from the cut-off state to the saturation state. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0020] Figure 1 This is a circuit diagram of the utility model. DETAILED DESCRIPTION

[0021] The following will describe the implementation methods of the present application in detail with reference to the accompanying drawings and examples, so that the implementation process of how the present application applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0022] like Figure 1As shown, the power protection circuit based on the non-intrusive power load monitoring terminal provided in this embodiment includes a transformer T1 and a transformer T2 connected in series. The transformer T2 is electrically connected to the transformer T3 through rectification and filtering. The terminal pins 1 and 5 of the transformer T3 are electrically connected to the high-power switch tube V3. The transformer T3 is electrically connected to the high-power switch tube V3 through the collector L22 and the collector L23. The 220V AC power is rectified and filtered to obtain a DC voltage of about 300V, which is then added to the collector L22 and the collector L23 of the high-power switch tube V3 through the terminal pins 1 and 5 windings of the transformer T3 to continue the impact of the pulse current on the electrode of the high-power switch tube V3. The terminal pins 7 and 9 windings of the transformer T3 are positive feedback windings, and their feedback current The potential is coupled to the base of the high-power switch tube V3 via resistor R26 and capacitor C19. Capacitors C23 and C24 can absorb the collector spike pulse of the high-power switch tube V3 to prevent the high-power switch tube V3 from breaking down and being damaged. The windings at pins 7 and 9 of transformer T3 are positive feedback windings. Their feedback potential is coupled to the base of the high-power switch tube V3 via resistor R26 and capacitor C19, thereby causing the high-power switch tube V3 to self-oscillate at a frequency of 30-60kHz. A diode VD39 is electrically connected to the collector L22. Diode VD39 provides a discharge circuit for the positive feedback coupling capacitor C19 and simultaneously limits the reverse voltage of the be-pole of the high-power switch tube V3 to 0-7V during the cut-off period to prevent the be-pole of the high-power switch tube V3 from breaking down.

[0023] The side of the diode VD39 away from the high-power switch tube V3 is electrically connected to the constant current drive tube V20, the high-power switch tube V21, the undervoltage protection control tube V38 and the overcurrent protection control tube V25. The end pins 8 and 7 of the transformer T3 are electrically connected to the diode VD20 and the capacitor C21, and are electrically connected to the constant current drive tube V20 through the resistor R22. The end pin 9 of the transformer T3 is connected to the constant current drive tube V20 through the resistor R23. The constant current drive tube V20 is a constant current drive tube. The end pins 8 and 7 of the transformer T3 are electrically connected to the constant current drive tube V20. The winding potential is rectified by the constant current drive tube VD20 and filtered by the capacitor C21 to establish a DC voltage of about 8V. This voltage is supplied to the collector of the constant current drive tube V20 through the resistor R22. During the saturation period of the high-power switch tube V3, the potential of the 9-pin of the transformer T3 turns on the constant current drive tube V20 through the resistor R23. Therefore, the constant current drive tube V20 provides a constant current drive current for the high-power switch tube V3. The value of the constant current drive current is determined by the resistance value of the resistor R22. The constant current drive expands the AC input voltage range of the switching power supply to 90-270V.

[0024] The high-power switch tube V21 is electrically connected to a diode VD44. The pins 8 and 7 of the transformer T3 are connected to the capacitor C33 through the diode VD43. The high-power switch tube V21 has two functions. The first is overvoltage protection. When the voltage across the capacitor C21 rises from the normal value of 8V to 10V, the diode VD44 breaks down and turns on, causing the high-power switch tube V21 to turn on. The base excitation current of the high-power switch tube V3 is short-circuited by the ce pole of the high-power switch tube V21, so that the high-power switch tube V3 is in the cut-off state and protected. The second function is to delay the conduction of the high-power switch tube V3. During the off-state of the switch V3, the positive potential of the terminal 8 and the negative potential of the terminal 7 of the transformer T3 are used to charge the capacitor C33 via the diode VD43. When the high-power switch V3 switches from the off-state to the saturation state, the charged voltage of the capacitor C33 will keep the high-power switch V21 on for a period of time. During this period, the high-power switch V21 shunts the excitation current of the base of the high-power switch V3, that is, the turn-on of the high-power switch V3 is delayed for a period of time. At this time, the collector voltage of the high-power switch V3 has dropped to a low point, thereby reducing the power loss caused by the instantaneous switch V3 switches from the off-state to the saturation state.

[0025] The terminal pins 7 and 9 of the transformer T3 are electrically connected to the capacitor C26 through the diode VD24. The capacitor C26 is electrically connected to the undervoltage protection control tube V38 through the resistors R69 and R67. The base of the undervoltage protection control tube V38 is electrically connected to the external 300V voltage through the resistor R68. The undervoltage protection control tube V38 is electrically connected to the high-power switch tube V24 and the high-power switch tube V22. The undervoltage protection control tube V38 is an undervoltage protection control tube. First, the terminal pin 7 of the transformer T3 is at a positive potential and the terminal pin 9 is at a negative potential. After being rectified by the diode VD24, a DC voltage of about -10V is established on the capacitor C26. This -10V voltage The voltage is applied to the base of the undervoltage protection control tube V38 through resistors R69 and R67. In addition, the 300V voltage is also applied to the base of the undervoltage protection control tube V38 through resistor R68. When the input AC voltage is lower than 110V, that is, the DC voltage obtained after rectification and filtering drops from 300V to below 150V, the base potential of the undervoltage protection control tube V38 also drops, so the undervoltage protection control tube V38 turns on, and then causes the high-power switch tubes V24 and V22 to turn on. The base excitation current of the high-power switch tube V3 is bypassed by the high-power switch tube V22, so that the high-power switch tube V3 is in the cut-off state and protection is performed;

[0026] The high-power switch tube V3 is electrically connected to a resistor R39. The resistor R39 is electrically connected to the base of the overcurrent protection control tube V25 through a resistor R33. The overcurrent protection control tube V25 is connected to the high-power switch tube V22. The overcurrent protection control tube V25 is an overcurrent protection control tube. The resistor R39 is the overcurrent detection resistor of the switch tube V3. The overcurrent voltage drop across the resistor R39 is applied to the base of the overcurrent protection control tube V25 through the resistor R33. When the overcurrent protection control tube V25 is turned on, the high-power switch tube V22 is turned on. As a result, the switch tube V3 is turned off due to the overcurrent.

[0027] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of the components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0028] It should be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or system. In the absence of further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of other identical elements in the product or system comprising the element.

[0029] The above description shows and describes several preferred embodiments of the present invention. However, as previously mentioned, it should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Instead, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the present invention as taught herein or through the techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the claims appended hereto.

Claims

1. A power protection circuit based on a non-intrusive power load monitoring terminal, comprising a transformer T1 and a transformer T2 connected in series, characterized in that: The transformer T2 is electrically connected to the transformer T3 through rectification and filtering. The pins 1 and 5 of the transformer T3 are electrically connected to the high-power switch V3. The transformer T3 is electrically connected to the high-power switch V3 through the collector L22 and the collector L23. The collector L22 is electrically connected to a diode VD39 , and the side of the diode VD39 away from the high-power switch tube V3 is electrically connected to a constant current drive tube V20 , a high-power switch tube V21 , an undervoltage protection control tube V38 , and an overcurrent protection control tube V25 .

2. The power protection circuit based on the non-intrusive power load monitoring terminal according to claim 1, characterized in that: The windings at the pins 7 and 9 of the transformer T3 are positive feedback windings, and the feedback potential thereof is coupled to the base of the high-power switch tube V3 via the resistor R26 and the capacitor C19.

3. The power protection circuit based on the non-intrusive power load monitoring terminal according to claim 1, characterized in that: The pins 8 and 7 of the transformer T3 are electrically connected to a diode VD20 and a capacitor C21, and are electrically connected to the constant current drive tube V20 through a resistor R22. The pin 9 of the transformer T3 is electrically connected to the constant current drive tube V20 through a resistor R23.

4. The power protection circuit based on the non-intrusive power load monitoring terminal according to claim 1, characterized in that: The high-power switch tube V21 is electrically connected to a diode VD44 , and the terminal pins 8 and 7 of the transformer T3 are connected to a capacitor C33 via a diode VD43 .

5. The power protection circuit based on the non-intrusive power load monitoring terminal according to claim 1, characterized in that: The pins 7 and 9 of the transformer T3 are electrically connected to a capacitor C26 via a diode VD24 , and the capacitor C26 is electrically connected to the undervoltage protection control tube V38 via resistors R69 and R67 .

6. The power protection circuit based on the non-intrusive power load monitoring terminal according to claim 1, characterized in that: The base of the undervoltage protection control tube V38 is electrically connected to the external 300V voltage through the resistor R68.

7. The power protection circuit based on the non-intrusive power load monitoring terminal according to claim 1, characterized in that: The undervoltage protection control tube V38 is electrically connected to the high-power switch tube V24 and the high-power switch tube V22.

8. The power protection circuit based on the non-intrusive power load monitoring terminal according to claim 1, characterized in that: The high-power switch tube V3 is electrically connected to a resistor R39 , which is electrically connected to the base of the overcurrent protection control tube V25 via a resistor R33 , and the overcurrent protection control tube V25 is connected to the high-power switch tube V22 .

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