Circuit breaker tripping control interface implementation system and method for fire-fighting scene

Abstract

The invention discloses a circuit breaker tripping control interface implementation system and method for a fire-fighting scene. The system comprises an auxiliary power supply rectifier bridge, an auxiliary power supply detection circuit and a tripping control circuit. After the fire-fighting auxiliary power supply is connected, on one hand, power is supplied to an existing switching power supply conversion circuit in the circuit breaker through a rectifier bridge, and a low-voltage direct-current power supply VCC is generated; and on the other hand, the isolated auxiliary power supply detection circuit generates an enabling control signal to trigger the tripping control circuit to work. The tripping control circuit adopts a pure hardware design (such as a 555 timer), and directly outputs a driving signal to control the action of the tripper, so that the tripping of the circuit breaker is realized. According to the invention, by multiplexing internal power source resources, embedded integration is realized, and space and cost are saved; electrical isolation detection and hardware independent driving are adopted, high safety and high reliability are ensured, and the system can be compatible with various alternating-current and direct-current fire-fighting auxiliary power supplies.

Description

Technical Field

[0001] This invention relates to the field of low-voltage electrical technology, specifically to a circuit breaker, and more particularly to a circuit breaker tripping control interface implementation system and method for fire protection scenarios. Background Technology

[0002] In building electrical distribution systems, electrical safety during fire is paramount. To prevent electrical faults from escalating the disaster and to ensure the safety of firefighters, relevant regulations require the mandatory disconnection of non-fire-fighting power supplies during a fire. This necessitates that circuit breakers possess a fire trip interface: upon receiving auxiliary control power (fire auxiliary power) from the fire protection system, the circuit breaker must immediately and reliably trip regardless of whether the main circuit is energized. This function should operate with the highest reliability, ideally independent of the circuit breaker's internal microcontroller (MCU) to prevent functional failure due to MCU program malfunctions, power outages, or other faults.

[0003] Currently, the main technical solutions for achieving this function have many limitations: Using a dedicated mechanical shunt trip accessory: This solution requires occupying valuable accessory mounting slots in the circuit breaker. For miniaturized, highly integrated intelligent circuit breakers, the internal space is compact, and accessory slots are often occupied by the main control board and signal feedback circuits, making it difficult to install shunt trip accessories, and the cost is relatively high.

[0004] Direct drive using an external isolated power supply circuit ("power backpack"): This solution requires an independent power supply circuit to be added outside the circuit breaker, which is inconvenient to install, occupies extra space in the distribution cabinet, and the external connection increases the number of fault points.

[0005] Direct drive using a built-in non-isolated RC step-down circuit poses a serious safety hazard. Because the circuit is not isolated, when connected to a fire-fighting power supply, dangerous voltages may be introduced onto external communication interfaces (such as non-isolated 485 buses) or the equipment casing, posing a risk of electric shock and equipment damage. Furthermore, the circuit has poor adaptability to input voltage.

[0006] In summary, existing solutions cannot simultaneously address space requirements, ease of installation, cost, and electrical safety, and therefore cannot provide a safe, reliable, universal, and space-saving fire tripping solution for compact smart circuit breakers. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a circuit breaker tripping control interface system and method for fire protection scenarios. This system reuses existing circuit resources within the circuit breaker and uses simple additional circuitry to achieve the detection and tripping of fire auxiliary power supply. It features a compact structure, low cost, high safety, strong compatibility, and high reliability without relying on an MCU.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A circuit breaker tripping control interface system for fire protection scenarios includes an auxiliary power rectifier bridge, an auxiliary power detection circuit, and a tripping control circuit. The input terminal of the auxiliary power rectifier bridge is connected to an external fire-fighting auxiliary power supply. The input terminal of the auxiliary power detection circuit is connected to the fire-fighting auxiliary power supply and generates an enable control signal when the fire-fighting auxiliary power supply is connected. The enable terminal of the tripping control circuit is connected to the output terminal of the auxiliary power detection circuit to receive the enable control signal. Its power supply terminal is connected to a low-voltage DC power supply VCC, and its output terminal is connected to the trip unit inside the circuit breaker. The low-voltage DC power supply VCC is generated by a switching power conversion circuit inside the multiplexed circuit breaker. The input terminal of this switching power conversion circuit can selectively connect to the output terminal of the auxiliary power rectifier bridge or the main circuit power supply of the circuit breaker. When the fire-fighting auxiliary power supply is connected, the enable control signal output by the auxiliary power detection circuit triggers the tripping control circuit to operate. The tripping control circuit outputs a drive signal to directly control the trip unit to trip the circuit breaker.

[0009] Furthermore, the switching power supply conversion circuit includes a main power rectifier bridge, a switching power supply controller, and an isolation transformer connected in sequence. The secondary side of the isolation transformer outputs the low-voltage DC power supply VCC. This part is an existing power supply circuit inside the circuit breaker. Through ingenious design, this invention enables it to be powered by an auxiliary power supply in fire-fighting mode, thus achieving the reuse of core power supply components.

[0010] Furthermore, the auxiliary power supply detection circuit includes a rectifier unit and a DC optocoupler UP1. The input terminal of the rectifier unit is connected to the fire-fighting auxiliary power supply. The light-emitting diode of the DC optocoupler UP1 is connected to the output circuit of the rectifier unit through a current-limiting resistor R1. The output terminal of the phototransistor of the DC optocoupler UP1 outputs the enable control signal. This design achieves electrical isolation between the high-voltage fire-fighting power supply and the low-voltage control circuit, ensuring safety, and is compatible with multiple AC and DC inputs.

[0011] Furthermore, a preferred embodiment of the trip control circuit includes an enable switch Q1, a pulse generation unit, and a drive switch Q2. The control terminal of the enable switch Q1 is connected to the enable control signal, its first path terminal is connected to VCC, and its second path terminal supplies power to the pulse generation unit. Upon power-up, the pulse generation unit generates a pulse sequence signal with a specific frequency and duty cycle. The control terminal of the drive switch Q2 is connected to the pulse sequence signal, its first path terminal is grounded (GND), and its second path terminal is used to connect to the trip unit. This method effectively prevents the trip coil from overheating due to prolonged energization by driving the trip with a narrow pulse.

[0012] Furthermore, the pulse generation unit includes a timer chip U1, resistors R3 and R4, and a timing capacitor C3. The timer chip U1 is a 555 timer or a compatible chip. Resistor R3 is connected between the discharge terminal and the power supply terminal of the timer chip U1. Resistor R4 and the timing capacitor C3 are connected in series between the discharge terminal of the timer chip U1 and ground. The trigger terminal and threshold terminal of the timer chip U1 are connected to the common node of resistor R4 and timing capacitor C3. The output terminal of the timer chip U1 outputs the pulse sequence signal.

[0013] Furthermore, the pulse generation unit also includes a diode D15. The anode of the diode D15 is connected to the discharge terminal of the timer chip U1, and its cathode is connected to the common node of the resistor R4 and the timing capacitor C3. The diode D15 is used to provide a fast discharge path for the capacitor C3.

[0014] Furthermore, the pulse generating unit also includes a diode D16. The anode of the diode D16 is connected to the common node of the resistor R4 and the timing capacitor C3, and its cathode is connected to the end of the resistor R4 closest to the common node. The diode D16 is used to ensure that during the charging process of the timing capacitor C3, the current must flow through the resistor R4, thereby achieving separation and precise control of the charging and discharging paths.

[0015] Furthermore, it also includes a filter capacitor C2, which is connected between the control voltage terminal of the timer chip U1 and ground GND.

[0016] Furthermore, the duty cycle of the pulse sequence signal is adjusted by the resistance ratio of resistors R3 and R4, and its frequency is adjusted by the total resistance of resistors R3 and R4 and the capacitance of timing capacitor C3, thereby achieving optimized control of the tripping action.

[0017] Furthermore, another simplified implementation of the trip control circuit includes an enable switch Q1 and a drive switch Q2. The control terminal of the enable switch Q1 is connected to the enable control signal, and its first path terminal is connected to VCC. The control terminal of the drive switch Q2 is connected to the second path terminal of the enable switch Q1 through a resistor R3. The first path terminal of the drive switch Q2 is grounded, and its second path terminal is used to connect to the trip unit. This method is suitable for scenarios where the external fire power supply control relay itself has a time-delay shutdown function, and the circuit is simpler.

[0018] Furthermore, the fire-fighting auxiliary power supply is AC220V, AC400V, DC110V or DC220V, and the system has good voltage compatibility.

[0019] This invention also provides a method for implementing a circuit breaker tripping control interface in fire protection scenarios. Using the aforementioned system, the method includes the following steps: when the fire auxiliary power supply is connected, it is rectified by an auxiliary power supply rectifier bridge and supplied to a switching power conversion circuit to generate VCC; simultaneously, an auxiliary power supply detection circuit detects and generates an enable control signal; this signal triggers the tripping control circuit to operate; the tripping control circuit generates a drive signal to directly drive the trip unit to operate. Preferably, the drive signal is a series of narrow pulses, and the duty cycle is controlled to prevent the trip coil from overheating.

[0020] The beneficial effects of this invention are as follows: (1) Embedded integration, saving space: The core control circuit is integrated inside the circuit breaker in the form of onboard, without occupying accessory compartments or external circuits, which is suitable for compact intelligent circuit breakers.

[0021] (2) Reuse resources and reduce costs: Make full use of the existing isolation switching power supply (main power rectifier bridge, switching power controller, isolation transformer) inside the circuit breaker to power the entire control circuit, reducing the number of additional power supply circuits and reducing costs.

[0022] (3) Electrical isolation, safe and reliable: By using DC optocoupler to detect the auxiliary power supply, the entire control circuit is electrically isolated from the high-voltage fire power supply, eliminating the risk of electric shock and damage caused by non-isolation schemes.

[0023] (4) Independent tripping with high reliability: The tripping drive signal is generated by a pure hardware circuit (555 timer, etc.) and directly drives the trip unit. The tripping process does not depend on the MCU, avoiding failure to operate due to MCU failure, and the reliability is extremely high.

[0024] (5) Strong compatibility: The circuit design is compatible with various common fire auxiliary power supply standards such as AC 220V / 400V and DC 110V / 220V.

[0025] (6) Protection device: The pulse drive method can effectively prevent the trip coil from overheating and being damaged due to prolonged energization. Attached Figure Description

[0026] Figure 1 This is a system overall circuit block diagram according to an embodiment of the present invention.

[0027] Figure 2 This is a detailed circuit diagram of Embodiment 1 of the present invention (including the 555 timer pulse generation circuit).

[0028] Figure 3 This is a circuit diagram of the tripping control circuit according to Embodiment 1 of the present invention.

[0029] Figure 4This is a simplified circuit diagram of the tripping control circuit according to Embodiment 2 of the present invention.

[0030] Figure 5 This is a simplified tripping control circuit diagram of Embodiment 2 of the present invention.

[0031] Figure 6 This is a wiring diagram for the application of the present invention.

[0032] As shown in the figure: D1-D14 are rectifier diodes, D15 and D16 are diodes, UP1 is a DC optocoupler, Q1 is a PMOS transistor, Q2 is an NMOS transistor, U1 is a timer chip, R1-R4 are resistors, C1 is a filter capacitor, C2 is a filter capacitor, and C3 is a timing capacitor. Detailed Implementation

[0033] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" or "linked" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. It should be noted that the terms "comprising," "including," or any other variations are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Example 1

[0035] like Figures 1 to 3 As shown, this embodiment provides a circuit breaker tripping control interface implementation system for fire protection scenarios. The system architecture is divided into two parts: the original basic functional circuit inside the circuit breaker ( Figure 1 The part not outlined by dashed lines), and the core functional circuit of the present invention ( Figure 1 (The part inside the dashed box). I. The original basic functional circuit inside the circuit breaker (i.e., the switching power supply conversion circuit).

[0036] The switching power supply conversion circuit includes a main power rectifier bridge, a switching power supply controller (represented by a function block in the figure), an isolation transformer, a filter capacitor C1, and a trip unit (coil).

[0037] The main power supply rectifier bridge consists of six rectifier diodes D1, D2, D3, D4, D5, and D6, forming a three-phase full-wave rectifier bridge. Specifically, the anodes of rectifier diodes D4, D5, and D6 are connected together to form the positive (+) DC output terminal of the rectifier bridge; the cathodes of rectifier diodes D1, D2, and D3 are connected together to form the negative (-) DC output terminal of the rectifier bridge; the anode of rectifier diode D1 is connected in series with the cathode of rectifier diode D4, the anode of rectifier diode D2 is connected in series with the cathode of rectifier diode D5, and the anode of rectifier diode D3 is connected in series with the cathode of rectifier diode D6. The LA, LB, and LC terminals of the three-phase main circuit power supply are connected to the series connection points of rectifier diodes D1 and D4, D2 and D5, and D3 and D6, respectively. The function of this rectifier bridge is to rectify the three-phase AC main circuit power supply (e.g., AC 400V) into pulsating DC power.

[0038] The switching power supply controller is an isolated switching power supply control unit consisting of an integrated pulse width modulation (PWM) control chip (such as UC2842, L6561, or a compatible chip) and its necessary minimum peripheral circuitry (such as a start-up resistor, feedback network, MOSFET drive circuit, etc., simplified as functional blocks in the figure). It has two power input terminals (VIN). The first power input terminal is connected to the positive (+) DC output terminal of the main power supply rectifier bridge, and the second power input terminal is connected to the negative (-) DC output terminal of the main power supply rectifier bridge. This switching power supply controller converts the rectified DC power into a high-frequency pulse sequence and sends it from its output drive terminal to the primary winding of the isolation transformer.

[0039] The isolation transformer is a high-frequency transformer. Its primary winding receives a high-frequency pulse sequence output from the switching power supply controller, while its secondary winding outputs a lower-voltage high-frequency pulse according to the designed turns ratio. One output terminal of the secondary winding is connected to the positive terminal of the filter capacitor C1, serving as the output point of the stable low-voltage DC power supply VCC; the other output terminal of the secondary winding is connected to the negative terminal of the filter capacitor C1, and both are connected to the system reference ground (GND). The transformer's core and winding structure ensure electrical isolation between the primary (high-voltage side) and secondary (low-voltage side), meeting safety specifications. Its turns ratio is designed according to the required low-voltage DC power supply VCC voltage (e.g., 12V or 24V).

[0040] The filter capacitor C1 is typically an electrolytic capacitor. Its positive terminal is connected to one output terminal of the secondary winding of the isolation transformer and the VCC output line, while its negative terminal is connected to the other output terminal of the secondary winding of the isolation transformer and system ground (GND). Its function is to filter and smooth the high-frequency pulse voltage output from the transformer secondary winding, thereby outputting a stable low-voltage DC power supply VCC with low ripple. The capacitance and voltage rating of the filter capacitor C1 are determined based on the voltage rating of the low-voltage DC power supply VCC and the load current.

[0041] The trip unit (coil) is an electromagnetic actuator comprising an inductor coil (i.e., the trip coil) wound on an iron core. One end of the coil is fixedly connected to the low-voltage DC power supply VCC. The other end of the coil serves as the controlled end, controlled by the internal MCU via power devices during normal circuit breaker opening and closing control; however, in the fire trip mode of this invention, this end is controlled by a newly added trip control circuit. When sufficient current flows through the coil, the generated electromagnetic force drives the mechanically coupled trip linkage or armature, ultimately releasing the circuit breaker's locking mechanism and achieving forced tripping. II. Core Functional Circuit

[0042] The core functional circuit includes an auxiliary power rectifier bridge, an auxiliary power detection circuit, and a tripping control circuit.

[0043] The input terminal of the auxiliary power rectifier bridge is used to connect to an external fire-fighting auxiliary power supply, rectifying the AC input of the auxiliary power supply and outputting it to power the switching power supply controller. The auxiliary power rectifier bridge consists of rectifier diodes D7, D8, D11, and D12 forming a full-bridge rectifier circuit. Specifically, the anodes of rectifier diodes D11 and D12 are connected together, forming the positive (+) DC output terminal of the rectifier bridge, which is connected to the first power input terminal of the switching power supply controller; the cathodes of rectifier diodes D7 and D8 are connected together, forming the negative (-) DC output terminal of the rectifier bridge, which is connected to the second power input terminal of the switching power supply controller; the anode of rectifier diode D7 and the cathode of rectifier diode D11 are connected in series, with a terminal block between them, forming one input terminal L of the auxiliary power rectifier bridge; the anode of rectifier diode D8 and the cathode of D12 are connected in series, with a terminal block between them, forming the other input terminal N of the auxiliary power rectifier bridge. The two output contacts of the fire auxiliary power supply (such as the output contacts AC220-L and AC220-N of the fire control center relay) are connected to the input terminals L and N, respectively. When the fire auxiliary power supply is connected, even if the main circuit of the circuit breaker (LA, LB, LC) is de-energized, this circuit can still provide DC input to the switching power supply controller, thereby enabling the secondary winding of the isolation transformer to normally output low-voltage DC power VCC. This ensures that the entire fire trip control circuit can still obtain working power when disconnected from the main circuit, realizing the "OR" logic selection of the power path.

[0044] The input terminal of the auxiliary power supply detection circuit is connected to the fire auxiliary power supply. When the fire auxiliary power supply is connected, it converts the AC input into a DC signal, generating an enable control signal to be output to the trip control circuit. The auxiliary power supply detection circuit includes a rectifier unit, a current-limiting resistor R1, and a DC optocoupler UP1. The input terminal of the rectifier unit is connected to the fire auxiliary power supply. The rectifier unit is another rectifier bridge circuit composed of rectifier diodes D9, D10, D13, and D14. Specifically, the anodes of rectifier diodes D13 and D14 are connected together to form the positive (+) DC output terminal of the rectifier bridge; the cathodes of rectifier diodes D9 and D10 are connected together to form the negative (-) DC output terminal of the rectifier bridge; the anode of rectifier diode D9 and the cathode of rectifier diode D13 are connected in series, with a terminal block between them to form one input terminal L of the rectifier unit; the anode of rectifier diode D10 and the cathode of D14 are connected in series, with a terminal block between them to form the other input terminal N of the rectifier unit. The two output contacts of the fire auxiliary power supply (such as the output contacts AC220-L and AC220-N of the fire control center relay) are connected to the input terminals L and N of the rectifier unit, respectively. The LED of the DC optocoupler UP1 is connected to the output circuit of the rectifier unit through a current-limiting resistor R1. Specifically, one end of the current-limiting resistor R1 is connected to the negative (-) terminal of the DC output of the rectifier unit, and the other end is connected to the anode of the LED of the DC optocoupler UP1; the cathode of the LED of the DC optocoupler UP1 is connected to the positive (+) terminal of the DC output of the rectifier unit; the base of the phototransistor of the DC optocoupler UP1 faces the LED, the emitter of the phototransistor is grounded to GND, and the collector (output terminal) of the phototransistor outputs an enable control signal to the trip control circuit. The DC pulsating voltage after rectification by the rectifier unit is limited by the current-limiting resistor R1, which drives the light-emitting diode inside the DC optocoupler UP1 to emit light, thereby saturating and turning on the phototransistor inside it. The collector of the phototransistor serves as the output terminal of this circuit, outputting a low-level effective enable control signal. This auxiliary power supply detection circuit realizes high-voltage isolation detection of the "present / absent" state of the fire auxiliary power supply.

[0045] The enable terminal of the trip control circuit is connected to the output terminal of the auxiliary power supply detection circuit to receive the enable control signal. Its power supply terminal is connected to a low-voltage DC power supply VCC, and its output terminal is used to connect to the trip unit inside the circuit breaker. In this embodiment, one structure of the trip control circuit includes an enable switch Q1, a resistor R2, a pulse generation unit, and a drive switch Q2.

[0046] The enable switch Q1 is a PMOS transistor, serving as the enable switch for the entire tripping control circuit. The control terminal (gate) of enable switch Q1 and one end of resistor R2 are both connected to the collector of the phototransistor in DC optocoupler UP1 (i.e., connected to the enable control signal). The first path terminal (source) of enable switch Q1 and the other end of resistor R2 are both connected to a low-voltage DC power supply VCC, keeping it off under normal conditions (DC optocoupler UP1 is off). The second path terminal (drain) of enable switch Q1 supplies power to the pulse generation unit.

[0047] When the DC optocoupler UP1 is turned on due to the connection of the fire auxiliary power supply, the low level at its output terminal (collector of the phototransistor) pulls down the gate potential of the enable switch Q1, making the gate-source voltage Vgs of the enable switch Q1 negative, and the enable switch Q1 turns on. After the enable switch Q1 turns on, the voltage at its second path terminal (drain) is close to the low-voltage DC power supply VCC, thereby providing the operating voltage for the power supply terminal (pin 8, VCC) and reset terminal (pin 4, RESET, active high) of the timer chip U1 (555 timer).

[0048] The pulse generation unit is an astable multivibrator composed of a timer chip U1 and its peripheral resistors R3 and R4, filter capacitor C2, timing capacitor C3, and diodes D15 and D16. The timer chip U1 is a 555 timer or a compatible chip. The power supply terminal (pin 8, VCC) and reset terminal (pin 4, RESET, active high) of the timer chip U1 (555 timer) are both connected to the second path terminal (drain) of the enable switch Q1. Resistor R3 is connected between the discharge terminal (pin 7, DISCH) and the power supply terminal (pin 8, VCC) of the timer chip U1. Resistor R4 and the timing capacitor C3 are connected in series between the discharge terminal (pin 7, DISCH) of the timer chip U1 and ground (GND). The trigger terminal (pin 2, TRIG) and threshold terminal (pin 6, THRES) of the timer chip U1 are connected to the common node (denoted as node A) of resistor R4 and timing capacitor C3. The output terminal (pin 3, OUT) of the timer chip U1 outputs a pulse sequence signal (rectangular pulse sequence). The anode of the diode D15 is connected to the discharge terminal (pin 7, DISCH) of the timer chip U1, and its cathode is connected to the common node (node ​​A) of the resistor R4 and the timing capacitor C3. Diode D15 provides a fast discharge path for capacitor C3. The anode of the diode D16 is connected to the common node (node ​​A) of the resistor R4 and the timing capacitor C3, and its cathode is connected to the end of the resistor R4 closest to the common node (node ​​A). Diode D16 ensures that during the charging process of the timing capacitor C3, the current must flow through the resistor R4, thereby achieving separation and precise control of the charging and discharging paths. The timer chip U1 of the pulse generation unit begins to oscillate after being powered on, outputting a series of pulse sequence signals (rectangular pulse sequences) with specific frequencies and duty cycles from its output terminal (pin 3). The duty cycle of the pulse sequence signal is adjusted by the ratio of the resistance values ​​of resistors R3 and R4 (the ratio of discharge time to charging time), and its frequency is jointly adjusted by the total resistance value of resistors R3 and R4 and the capacitance value of the timing capacitor C3, thereby achieving optimized control of the tripping action. The filter capacitor C2 is connected between the control voltage terminal (pin 5, CONT) of the timer chip U1 and ground GND, used to filter out power supply noise and stabilize the reference voltage of the internal comparator. The ground terminal (pin 1, GND) of the timer chip U1 is grounded to GND.

[0049] The driving switch Q2 is an NMOS transistor used as the final power driving switch. The control terminal (gate) of the driving switch Q2 is connected to the output terminal (pin 3, OUT) of the timer chip U1 to receive pulse sequence signals. The first path terminal (source) of the driving switch Q2 is grounded to GND, and the second path terminal (drain) of the driving switch Q2 is used to connect to the trip unit (coil). The driving switch Q2 drives the trip by outputting narrow pulses, which effectively prevents the coil of the trip unit from overheating due to prolonged energization. Working principle:

[0050] When a fire occurs, the fire protection system control relay closes, connecting the fire auxiliary power supply (such as AC220V) to the L and N terminals of the system. The system then operates according to the following timing sequence: (1) Power supply setup: The fire auxiliary power supply is supplied to the switching power supply controller through the auxiliary power supply rectifier bridge (rectifier diodes D7, D8, D11, D12). After being filtered by the isolation transformer and the filter capacitor C1, a low-voltage DC power supply VCC is generated.

[0051] (2) Enable triggering: The other path of the fire auxiliary power supply is detected by the auxiliary power supply detection circuit (rectifier diodes D9, D10, D13, D14, resistor R1, DC optocoupler UP1). When DC optocoupler UP1 is turned on, its output terminal (collector) becomes low level and outputs an enable control signal.

[0052] (3) Pulse Generation: A low-level enable control signal turns on the enable switch Q1 (PMOS transistor), and the low-voltage DC power supply VCC supplies power to the timer chip U1 (555 timer) through the drain of the enable switch Q1. The timer chip U1 starts oscillating immediately after power-on. Its working process is as follows: Initial state: Assume the timer chip U1 outputs a high level, and the internal discharge transistor is off. At this time, the low-voltage DC power supply VCC charges the timing capacitor C3 through resistor R4 and diode D16. The charging current path is: VCC → resistor R4 → diode D16 → timing capacitor C3 → GND. The voltage across the timing capacitor C3 (i.e., the voltage at node A) starts to rise from a low level.

[0053] Flip 1: When the voltage of the timing capacitor C3 rises to more than (2 / 3) VCC, the threshold comparator inside the timer chip U1 flips, causing the output to become low level, and at the same time the internal discharge tube is turned on.

[0054] Discharge Phase: Timer chip U1 outputs a low level, and the internal discharge transistor pulls pin 7 (DISCH) low to near ground. At this time, the charge stored in timing capacitor C3 discharges rapidly through two paths: one is through diode D15 directly to pin 7 of timer chip U1 (main discharge path); the other is through resistor R3 to pin 7 of timer chip U1. The discharge current paths are: positive terminal of timing capacitor C3 (node ​​A) → diode D15 → pin 7 of timer chip U1 (internal discharge transistor) → GND; and positive terminal of timing capacitor C3 → resistor R3 → pin 7 of timer chip U1 (internal discharge transistor) → GND. The voltage of timing capacitor C3 drops rapidly.

[0055] Flip 2: When the voltage of timing capacitor C3 drops below (1 / 3) VCC, the comparator inside timer chip U1 flips, the output goes high again, the internal discharge transistor is cut off, and the charging process restarts. This cycle repeats, generating a series of rectangular pulses at pin 3 (OUT) of timer chip U1. The high-level time (charging time) is mainly determined by resistor R4 and timing capacitor C3; the low-level time (discharging time) is mainly determined by resistor R3 and timing capacitor C3. Due to the presence of diode D15, discharging is much faster than charging, thus generating narrow pulses with a very small duty cycle.

[0056] (4) Trip Drive: The narrow pulse sequence output by the timer chip U1 drives the drive switch Q2 (NMOS transistor). When the pulse is high, the drive switch Q2 is turned on; when it is low, the drive switch Q2 is turned off. The periodic turning on and off of the drive switch Q2 results in a pulsating voltage across the trip unit: when the drive switch Q2 is on, the voltage across the trip unit is close to VCC, generating an electromagnetic force; when the drive switch Q2 is off, the current is zero. This pulsating electromagnetic force is sufficient to drive the trip mechanism to trip the circuit breaker. Because the drive signal is a narrow pulse, the average power of the trip coil is very small, effectively avoiding overheating damage caused by prolonged energization.

[0057] The entire control process is implemented entirely by hardware circuitry, bypassing the internal MCU of the circuit breaker, thus ensuring the highest level of operational reliability. Example 2

[0058] like Figure 4 and Figure 5 As shown, this embodiment provides a simplified trip control circuit scheme. This scheme is suitable for scenarios where the control relay of the on-site fire auxiliary power supply itself has a delayed output function (for example, after the relay is turned on, it can automatically maintain the on state for hundreds of milliseconds to 1 second, and then automatically disconnect). The only difference between this embodiment and Embodiment 1 is the different trip control circuit.

[0059] In this embodiment, the trip control circuit is significantly simplified, comprising only an enable switch Q1 (PMOS transistor), resistors R2 and R3, and a drive switch Q2 (NMOS transistor). The connections are as follows: the output terminal (collector of the phototransistor) of the DC optocoupler UP1 is connected to the gate of the enable switch Q1 and one end of resistor R2 (pull-up resistor). The other end of resistor R2, along with the source of the enable switch Q1, is connected to the low-voltage DC power supply VCC. The drain of the enable switch Q1 is connected to one end of the drive resistor R3 and the gate of the drive switch Q2. The other end of resistor R3, along with the source of the drive switch Q2, is grounded to GND. The drain of the drive switch Q2 is connected to the other end of the trip unit (the upper end of the trip unit is still connected to the low-voltage DC power supply VCC). Working principle:

[0060] When the fire auxiliary power supply is connected, the DC optocoupler UP1 conducts and outputs a low-level EN signal, enabling switch Q1 turns on. VCC forms a voltage between the gate of drive switch Q2 and ground GND through the conducting enable switch Q1 and resistor R3. If the resistance value of resistor R3 is designed properly, this voltage is sufficient to make the gate-source voltage Vgs of drive switch Q2 exceed its turn-on threshold, thereby turning on drive switch Q2. After drive switch Q2 turns on, a complete current loop is formed: VCC → trip unit (coil) → Q2 (from drain to source) → GND. The trip unit is energized and generates a pulling force, and the drive mechanism trips. Since the external fire relay will turn off with a delay, this drive signal is a DC signal lasting several hundred milliseconds, which is sufficient to ensure that the trip action is completed. Subsequently, the power supply is cut off, which also avoids long-term heating of the trip coil. This scheme eliminates the 555 timer and related peripheral circuits, resulting in lower cost. When meeting specific application conditions (external relay has a delay), it is an effective simplified implementation. Example 3

[0061] The fire-fighting auxiliary power supply described in Embodiment 1 or Embodiment 2 is AC220V, AC400V, DC110V or DC220V, and the system has good voltage compatibility.

[0062] Application wiring method like Figure 6 As shown, the system of this invention is connected to the control relay output of an external fire auxiliary power supply via two clearly marked terminals (L and N). Wiring is simple and flexible, and it is compatible with multiple power supply systems. When the fire auxiliary power supply is AC220V or AC400V, the L and N terminals are connected to the live wire and neutral wire of the AC power supply respectively (for 400V, they are two-phase wires), and there is no need to distinguish the polarity.

[0063] When the fire auxiliary power supply is DC220V or DC110V, the L terminal is connected to the positive terminal (DC+) of the DC power supply, and the N terminal is connected to the negative terminal (DC-) of the DC power supply.

[0064] In this invention, the DC input terminals (VIN+ and VIN-) of the switching power supply controller are directly connected in parallel with the output terminals (+, -) of the main power supply rectifier bridge and the output terminals (+, -) of the auxiliary power supply rectifier bridge, respectively. Due to the unidirectional conductivity of the rectifier diodes, the outputs of the two rectifier bridges form a natural 'OR' logic in the circuit. When the main circuit is powered, it is supplied by the main power supply rectifier bridge; when the main circuit is de-energized but the fire auxiliary power supply is connected, it is supplied by the auxiliary power supply rectifier bridge, thereby realizing seamless automatic switching of the power input path.

[0065] Firefighting auxiliary power typically originates from the output relay contacts (normally open contacts) of the fire alarm control system. When a fire occurs, these contacts close, connecting the mains power (AC220V / 400V) or a dedicated fire-fighting DC power supply (DC110V / 220V) to the system. The interface circuit of this invention functions as a pure load, consuming only electrical energy to drive the trip, requiring no external control signals, and its wiring is simple and reliable.

[0066] The circuit of this invention has a full-bridge rectifier structure, so it can automatically adapt to the above AC and DC inputs and automatically correct the polarity, which greatly facilitates on-site installation and debugging.

[0067] The circuit of this invention has a full-bridge rectifier structure, thus it can automatically adapt to the aforementioned AC / DC inputs and automatically correct polarity, greatly facilitating on-site installation and debugging. Other aspects of this invention not detailed herein are conventional techniques known to those skilled in the art.

[0068] It should be noted that the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0069] The scope of protection of this invention is not limited to the technical solutions disclosed in the specific embodiments. Any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of this invention shall fall within the scope of protection of this invention.

Claims

1. A circuit breaker tripping control interface implementation system for fire protection scenarios, characterized in that: This includes an auxiliary power rectifier bridge, an auxiliary power detection circuit, and a trip control circuit; The input terminal of the auxiliary power rectifier bridge is used to connect to an external fire-fighting auxiliary power supply. The input terminal of the auxiliary power supply detection circuit is connected to the fire auxiliary power supply, and is used to generate an enable control signal when the fire auxiliary power supply is connected. The enable terminal of the trip control circuit is connected to the output terminal of the auxiliary power supply detection circuit to receive the enable control signal. The power supply terminal of the trip control circuit is connected to a low-voltage DC power supply VCC, and its output terminal is used to connect to the trip unit inside the circuit breaker. The low-voltage DC power supply VCC is generated by the switching power conversion circuit inside the multiplex circuit breaker. The input terminal of the switching power conversion circuit can be selectively connected to the output terminal of the auxiliary power rectifier bridge or the main circuit power supply of the circuit breaker. When the fire auxiliary power supply is connected, the enable control signal output by the auxiliary power supply detection circuit triggers the trip control circuit to work. The trip control circuit outputs a drive signal to directly control the trip unit to trip the circuit breaker.

2. The circuit breaker tripping control interface implementation system for fire protection scenarios according to claim 1, characterized in that: The switching power supply conversion circuit includes a main power rectifier bridge, a switching power supply controller, and an isolation transformer connected in sequence. The secondary side of the isolation transformer outputs the low-voltage DC power supply VCC.

3. The circuit breaker tripping control interface implementation system for fire protection scenarios according to claim 1, characterized in that: The auxiliary power supply detection circuit includes a rectifier unit and a DC optocoupler UP1; The input terminal of the rectifier unit is connected to the fire-fighting auxiliary power supply; The LED of the DC optocoupler UP1 is connected to the output circuit of the rectifier unit through a current-limiting resistor R1; The enable control signal is output from the phototransistor of the DC optocoupler UP1.

4. The circuit breaker tripping control interface implementation system for fire protection scenarios according to claim 1, characterized in that: The tripping control circuit includes an enable switch Q1, a pulse generation unit, and a drive switch Q2; The control terminal of the enable switch Q1 is connected to the enable control signal, its first path terminal is connected to the low-voltage DC power supply VCC, and its second path terminal supplies power to the pulse generation unit. After being powered on, the pulse generating unit generates a pulse sequence signal with a specific frequency and duty cycle. The control terminal of the drive switch Q2 is connected to the pulse sequence signal, its first path terminal is grounded to GND, and its second path terminal is used to connect to the trip unit.

5. The circuit breaker tripping control interface implementation system for fire protection scenarios according to claim 4, characterized in that: The pulse generation unit includes a timer chip U1, resistor R3, resistor R4, and timing capacitor C3; The timer chip U1 is a 555 timer or a compatible chip; The power supply terminal of the timer chip U1 is connected to the second path terminal of the enable switch Q1, and its ground terminal is grounded to GND. The resistor R3 is connected between the discharge terminal and the power supply terminal of the timer chip U1. The resistor R4 and the timing capacitor C3 are connected in series between the discharge terminal of the timer chip U1 and ground GND. The trigger terminal and threshold terminal of the timer chip U1 are connected to the common node of the resistor R4 and the timing capacitor C3; The pulse sequence signal is output from the output terminal of the timer chip U1.

6. The circuit breaker tripping control interface implementation system for fire protection scenarios according to claim 5, characterized in that: It also includes diodes D15 and D16. The anode of diode D15 is connected to the discharge terminal of the timer chip U1, and its cathode is connected to the common node of resistor R4 and timing capacitor C3. The anode of diode D16 is connected to the common node of resistor R4 and timing capacitor C3, and its cathode is connected to the end of resistor R4 closest to the common node.

7. The circuit breaker tripping control interface implementation system for fire protection scenarios according to claim 5, characterized in that: The duty cycle of the pulse sequence signal is adjusted by the ratio of the resistance values ​​of resistors R3 and R4, and its frequency is adjusted by the total resistance value of resistors R3 and R4 and the capacitance value of timing capacitor C3.

8. The circuit breaker tripping control interface implementation system for fire protection scenarios according to claim 1, characterized in that: The tripping control circuit includes an enable switch Q1 and a drive switch Q2; The control terminal of the enable switch Q1 is connected to the enable control signal, and its first path terminal is connected to the low-voltage DC power supply VCC. The control terminal of the drive switch Q2 is connected to the second path terminal of the enable switch Q1 through a resistor R3. The first path terminal of the drive switch Q2 is grounded, and its second path terminal is used to connect to the trip unit.

9. The circuit breaker tripping control interface implementation system for fire protection scenarios according to claim 1, characterized in that: The fire-fighting auxiliary power supply is AC220V, AC400V, DC110V or DC220V.

10. A method for implementing a circuit breaker tripping control interface for fire protection scenarios, characterized in that, The system is implemented using the circuit breaker tripping control interface for fire protection scenarios as described in any one of claims 1-9, and the method includes the following steps: When the fire auxiliary power supply is connected, it is rectified by the auxiliary power rectifier bridge and supplied to a switching power conversion circuit to generate a low-voltage DC power supply VCC. The auxiliary power supply detection circuit detects the connection of the fire-fighting auxiliary power supply and generates an enable control signal. The trip control circuit is triggered to start working using the enable control signal; The trip control circuit generates a drive signal, which directly drives the trip unit to trip the circuit breaker.

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