CN109687390B - Tracking type electronic fire-proof controller and control method thereof - Google Patents
Tracking type electronic fire-proof controller and control method thereof Download PDFInfo
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- CN109687390B CN109687390B CN201910105665.1A CN201910105665A CN109687390B CN 109687390 B CN109687390 B CN 109687390B CN 201910105665 A CN201910105665 A CN 201910105665A CN 109687390 B CN109687390 B CN 109687390B
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- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/087—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for DC applications
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Abstract
The invention relates to a tracking electronic fire-proof controller and a control method thereof, wherein the control method is that a rectifier bridge is connected on an AC power supply line forming an AC loop, the output end of the rectifier bridge is connected with a switch tube and a load current sampling resistor to form a DC control loop for controlling the on-off of the AC loop, the control electrode of the switch tube is connected with a signal control circuit, when the load current sampling resistor detects that the load current is abnormal, the signal control circuit sends a turn-off signal to turn off the switch tube, the DC control loop is cut off, the rectifier bridge cuts off the AC power supply line, and a rapid electronic self-locking switch keeps the switch tube in a continuous turn-off state through a self-locking function to keep the load in the AC loop in a power-off state, thereby realizing the short circuit, overload and virtual connection protection of the load and the power supply line. The invention can be suitable for the electric safety protection in various places, can replace control cabinets of various machine tools, electrical equipment and the like, and can also be directly used as an intrinsically safe explosion-proof product.
Description
Technical Field
The invention relates to a fire-proof safety device, in particular to a tracking electronic fire-proof controller and a control method thereof.
Background
The electrical appliance often causes electrical fire due to factors such as virtual connection, overload, short circuit, ignition and the like of a circuit, so that serious fire accidents caused by the electrical fire often occur at all terminals, and the great loss of lives and properties of people is caused. There are three causes of electrical fires: short-circuit ignition, virtual spark ignition (also known as split firing), and local failure or local short-circuit to generate high temperature. In order to avoid fire accidents, electrical appliances are often equipped with various auxiliary electrical appliances such as overcurrent relays, time relays, contactors and the like. The auxiliary electrical appliances have various models and different application occasions, and the key point is that the auxiliary electrical appliances are matched with the large-current starting power of the electrical appliances, so that the protection insurance value is generally set to be higher than a normal operation value, otherwise, the auxiliary electrical appliances are difficult to start and have the necessary protection effect.
The virtual connection of the line is a common factor causing electrical fire, and the process is that due to poor connection of the line, the internal resistance is increased to cause instantaneous open circuit, and the gap of the open circuit fracture is very small, so that gap discharge is easily generated, and continuous pulse sparks are formed due to repeated occurrence of the discharge process, so that fire accidents are caused.
Disclosure of Invention
The invention aims to provide a tracking type electronic fire-proof controller and a control method thereof, which aim to solve the problem that the existing electrical control cabinet frequently generates electrical fire accidents due to the fact that protection devices are not configured properly or are not configured.
The invention is realized by the following steps: a tracking electronic fire protection controller, comprising:
the virtual connection detection protection circuit is respectively connected with the short-circuit protection switch circuit and the signal control circuit and is used for monitoring an open-circuit signal of an electrical appliance or a power supply line and sending a virtual connection power-off signal to the short-circuit protection switch circuit and the signal control circuit when the virtual connection condition is judged to occur;
the overload detection control circuit is respectively connected with the short-circuit protection switch circuit and the signal control circuit and is used for monitoring the overcurrent or local short-circuit condition of the electrical appliance and sending an overload power-off signal to the short-circuit protection switch circuit and the signal control circuit when judging that the overload condition occurs;
the short-circuit protection switch circuit is respectively connected with the virtual connection detection protection circuit, the overload detection control circuit, the signal control circuit and the power circuit and is used for disconnecting the power circuit through the rapid electronic self-locking switch circuit when short-circuit, virtual connection or overload occurs to an electric appliance and a power supply line;
the starting current tracking and adjusting circuit is connected with the signal control circuit and is used for tracking the starting current of the electric appliance and correspondingly adjusting the protection value along with the change of the starting current;
the signal control circuit is respectively connected with the virtual connection detection protection circuit, the overload detection control circuit, the short-circuit protection switch circuit and the starting current tracking and adjusting circuit and is used for indicating the instant states of the electric appliance and the power supply line; and
and the power supply circuit provides alternating current working voltage for the load and provides direct current working voltage for the circuits of all the parts.
The circuit of the power supply circuit is formed in a way that an alternating current input end is connected with an alternating current output end through a fuse BX1, a capacitor C1 and a voltage dependent resistor Ry1 are connected in parallel between two connecting terminals of the alternating current input end, the original side of a transformer B1 is connected with leads from the two connecting terminals of the alternating current input end, the negative side of the transformer B1 is divided into two paths after passing through a rectifier bridge ZQ2 and a filter capacitor C2, one path is connected with the input end of a voltage stabilizer IC1, the voltage stabilizer IC1 outputs +12V direct current working voltage, the other path is connected with the input end of a voltage stabilizer IC2, and the voltage stabilizer IC2 outputs +5V direct; the output of stabiliser IC1 is behind filter capacitor C3 and electric capacity C4, be connected to triode Q5's projecting pole, stabiliser IC 2's output is behind filter capacitor C5 and electric capacity C6, series connection resistance R10, it is anodal to be reconnected to opto-coupler GO 1's input, opto-coupler GO 1's input negative pole connects signal control circuit, opto-coupler GO 1's output negative pole ground connection, the base of triode Q5 is received through base resistance R11 to opto-coupler GO 1's output positive pole, triode Q5's collecting electrode connects the collecting electrode of triode Q4 of short-circuit protection switching circuit through resistance R9.
The short-circuit protection switch circuit is formed by connecting an input end of a rectifier bridge ZQ1 on one power line connected with an alternating current output end, the cathode of the output end of the rectifier bridge ZQ1 is grounded, the anode of the output end is connected with the input electrode of a switch tube Q1, the control electrode of the switch tube Q1 is connected with a resistor R9 in a power circuit, the output electrode of a switch tube Q1 is divided into three paths, the first path is grounded through a load current sampling resistor R2, the second path is connected with a connecting terminal ZA1 for tapping an overload detection control circuit and a virtual connection detection protection circuit, the third path is connected with the base electrode of a triode Q2 through a resistor R3, the collector electrode of the triode Q2 is connected with the +12V direct current voltage output end of the power circuit through a resistor R4 and a resistor R5 which are connected in series to obtain a +12V direct current working voltage, a lead is connected to the connecting node of the resistor R4 and the resistor R5, one path is connected with a connecting, the other circuit is connected with the base electrode of a triode Q3, the emitter electrode of a triode Q3 is connected with the +12V direct-current voltage output end of a power circuit, the collector electrode of a triode Q3 is divided into three circuits, the first circuit is connected with a connecting terminal ZA2 used for being connected with an overload detection control circuit through a resistor R6, the second circuit is connected with a resistor R18 in a signal control circuit so as to output a short-circuit signal to the signal control circuit, the third circuit is grounded through a resistor R7 and a resistor R8, the base electrode of a triode Q4 is connected with a lead on the connecting node of a resistor R7 and a resistor R8, the emitter electrode of a triode Q4 is grounded, the collector electrode of a triode Q4 is divided into two circuits, one circuit is connected with the control electrode of a switching tube Q.
The tracking electronic fire-proof controller of the invention has the following characteristics:
1. a high-speed electronic device is adopted for rapid identification and response, a short circuit signal with the rising rate exceeding 50A/mu S can be captured in 1 mu S, the power supply is cut off in 1 mu S, and the generation of short circuit sparks can be completely avoided; and the power supply is not cut off when the high-current of the electric equipment is started.
2. When a virtual connection (representing that the circuit is disconnected and reconnected) phenomenon occurs in a circuit system, the power supply is quickly cut off, and a fire accident caused by the fact that the virtual connection is ignited is avoided; and the faults or damages caused by the impact current to the electrical equipment can be avoided.
3. The set safety value is a current protection value when the circuit normally operates; for the large current generated when the electrical equipment is started, the tracking type electronic fire-proof controller is automatically set randomly according to a normal starting curve, and automatically recovers to an operation protection value after the starting process is finished, so that the equipment or the electrical equipment cannot generate fire hazard when in normal operation, and cannot operate with diseases by using the electrical equipment.
The tracking electronic fire-proof controller can effectively avoid the occurrence of electrical fire accidents caused by virtual connection, overload, short circuit, ignition and the like of electrical appliances or power supply lines, has no spark due to direct short circuit, and is an omnibearing fire-proof electronic control switch with ultrahigh-speed detection, identification and control functions. The safety value can be automatically adjusted, so that the high-current protection device can automatically adapt to the large-current starting of any load, various auxiliary electrical devices such as an overcurrent relay, a time relay, a contactor and the like which are necessary to be used by a conventional protection electrical appliance can be omitted, and the protection safety value can be automatically adapted and adjusted in real time, so that the defects that the protection safety value of the conventional auxiliary electrical device is generally higher or the equipment runs with diseases and the like are overcome, and the complete protection of the electrical equipment can be realized.
The invention can also be realized as follows: a tracking electronic fire-proof control method is characterized by that a rectifier bridge is connected on an AC power supply line forming AC circuit, the output end of the rectifier bridge is connected with switch tube and load current sampling resistor, so as to form a direct current control loop for controlling the on-off of the alternating current loop, the control electrode of the switch tube is connected with a signal control circuit, when the load current sampling resistor detects that the load current is abnormal, the signal control circuit sends out a turn-off signal to turn off the switch tube and disconnect the direct current control loop, and the rectifier bridge accordingly disconnects the alternating current power supply circuit, the fast electronic self-locking switch keeps the switch tube in a continuous turn-off state through the self-locking function, so that the load in the alternating current loop keeps a power-off state (needs to be restarted after short circuit and virtual connection phenomena occur), the fault is prevented from continuously spreading or damaging the electric appliance, and short circuit and overload protection of the load and a power supply line is realized.
The tracking overload protection circuit is connected to the fast electronic self-locking switch to automatically regulate the current insurance value of the load, adapt to the large-current starting of various loads and distinguish the starting current from the overload current.
The quick electronic self-locking switch is connected with a virtual connection detection protection circuit to detect the virtual connection generated in a load and a power supply line, when the virtual connection is detected, the control circuit sends out an instruction signal to turn off the switch tube, and the alternating current power supply line is cut off by using the rectifier bridge to realize the virtual connection protection of the circuit system.
The invention is suitable for the power consumption safety protection of production enterprises, various buildings, residential houses and the like, can replace control cabinets of various machine tools, electrical equipment and the like, can greatly reduce the configuration cost, has more perfect and reliable control performance, and can avoid the ill operation and the diffusion of faults of the electrical equipment. Because the safety is high and the safety completely meets various technical requirements of intrinsic safety type explosion-proof products, the safety type explosion-proof product can be directly used as an intrinsic safety type explosion-proof product to be applied to explosion-proof places.
Drawings
Fig. 1 is a block circuit diagram of the controller of the present invention.
Fig. 2 is a schematic circuit diagram of the power supply circuit and the short-circuit protection switch circuit.
Fig. 3 is a circuit schematic diagram of two parts of a starting current tracking adjustment circuit and an overload detection control circuit.
Fig. 4 is a circuit schematic of the virtual earth fault detection protection circuit.
Fig. 5 is a circuit schematic of the signal control circuit.
Detailed Description
As shown in fig. 1, the tracking electronic fire-proof controller of the present invention includes a power circuit 1, a short-circuit protection switch circuit 2, a signal control circuit 3, a starting current tracking adjustment circuit 4, an overload detection control circuit 5, a virtual connection detection protection circuit 6, and the like. The virtual connection detection protection circuit 6 is respectively connected with the short-circuit protection switch circuit 2 and the signal control circuit 3 and is used for monitoring an open-circuit signal of an electrical appliance or a power supply line and sending a virtual connection power-off signal to the short-circuit protection switch circuit and the signal control circuit when the virtual connection condition is judged to occur. The overload detection control circuit 5 is respectively connected with the short-circuit protection switch circuit 2 and the signal control circuit 3, and is used for monitoring the overcurrent or local short-circuit condition of the electrical appliance and sending an overload power-off signal to the short-circuit protection switch circuit and the signal control circuit when judging that the overload condition occurs. The short-circuit protection switch circuit 2 is respectively connected with the virtual connection detection protection circuit 6, the overload detection control circuit 5, the signal control circuit 3 and the power circuit 1 and is used for switching off the power circuit through the rapid electronic self-locking switch circuit when short-circuit, virtual connection or overload occurs to an electric appliance and a power supply line. The starting current tracking and adjusting circuit 4 is respectively connected with the overload detection control circuit 5 and the signal control circuit 3, and is used for tracking the starting current of the electric appliance and correspondingly adjusting the protection value along with the change of the starting current. The signal control circuit 3 is respectively connected with the virtual connection detection protection circuit 6, the overload detection control circuit 5, the short-circuit protection switch circuit 2 and the starting current tracking adjustment circuit 4, and is used for indicating the instant states of the electric appliance and the power supply line. The power supply circuit 1 is connected to the above-mentioned parts, and supplies the load with an ac operating voltage and also supplies the above-mentioned parts with a dc operating voltage.
The power supply circuit 1 comprises two parts, a 12V2A power supply and a 5V1A power supply. The response time of the short-circuit protection switch circuit 2 is below 1 [ mu ] S, and meanwhile, the short-circuit protection switch circuit also has a function of controlling virtual connection and disconnection. The signal control circuit 3 is responsible for the indication of the instantaneous state of the circuit, such as running, short-circuit, virtual connection and overload conditions. The starting current tracking and adjusting circuit 4 is characterized in that when the electric appliance is normally started (the current rising rate is not more than 50A/mu S, if the current rising rate exceeds the current rising rate, the electric appliance is regarded as a short circuit), the current rapidly rises, the safety value also rises, the starting current is from low to high and then from high to low, and the safety value when the starting current falls to the current balance is the normal operation value. The overload detection control circuit 5 implements accurate detection and protection when overcurrent or local short circuit occurs, so as to effectively avoid the continuous diffusion of faults or damage to the electric appliance. The virtual connection detection protection circuit 6 detects an open circuit signal at any time, sends out a virtual connection signal when the circuit is reconnected after being opened, and immediately cuts off a power supply circuit to avoid the generation of virtual connection sparks.
As shown in fig. 2, the specific circuit structure of the power supply circuit 1 is that an ac input end is connected to an ac output end through a fuse BX1, a capacitor C1 and a varistor Ry1 are connected in parallel between two terminals of the ac input end, an original side of a transformer B1 is connected from the two terminals of the ac input end by leads, a negative side of the transformer B1 is divided into two paths after passing through a rectifier bridge ZQ2 and a filter capacitor C2, one path is connected to an input end of a regulator IC1, +12V dc working voltage is output by a regulator IC1, the other path is connected to an input end of a regulator IC2, and +5V dc working voltage is output by a regulator IC 2; the output of stabiliser IC1 is behind filter capacitor C3 and electric capacity C4, be connected to triode Q5's projecting pole, stabiliser IC 2's output is behind filter capacitor C5 and electric capacity C6, series connection resistance R10, it is anodal to be reconnected to opto-coupler GO 1's input, opto-coupler GO 1's input negative pole connects signal control circuit, opto-coupler GO 1's output negative pole ground connection, opto-coupler GO 1's output positive pole is received triode Q5's base through base resistance R11, triode Q5's collecting electrode connects triode Q4's in the short-circuit protection switch circuit 2 collecting electrode through resistance R9.
The short-circuit protection switch circuit 2 has the specific circuit structure that the input end of a rectifier bridge ZQ1 is connected on one power line connected with an alternating current output end, the cathode (namely the anode of a diode) of the output end of the rectifier bridge ZQ1 is grounded, the anode (namely the cathode of the diode) of the output end is connected with the drain electrode of a field effect tube Q1 used as a switch tube, the grid electrode of the field effect tube Q1 is connected with a resistor R9 in the power circuit 1, one path is connected with the ground wire through a discharge resistor R1, the source electrode of the field effect tube Q1 is divided into three paths, the first path is grounded through a load current sampling resistor R2, the second path is connected with an overload detection control circuit 5 and a virtual connection detection protection circuit 6 through a ZA1 end, the third path is connected with the base electrode of a triode Q2 through a resistor R3, the collector electrode of the triode Q2 is connected with a +12V voltage output end of the power circuit after being connected with the resistor R4 and the resistor R5 in series, one path is connected with a virtual connection detection protection circuit 6 through ZA3, the other path is connected with the base electrode of a triode Q3, the emitter electrode of the triode Q3 is connected with the +12V direct-current working voltage output end of a voltage stabilizer IC1 in the power circuit 1, the collector electrode of the triode Q3 is divided into three paths, the first path is connected with an overload detection control circuit 5 through a resistor R6 and a diode D1 through ZA2, the second path is connected with a resistor R18 in the signal control circuit 3 to output a short-circuit signal to the signal control circuit 3, the third path is grounded through a resistor R7 and a resistor R8, the base electrode of the triode Q4 is connected with a lead wire at the connection node of the resistor R7 and the resistor R8, the emitter electrode of the triode 596Q 2 is grounded, the collector electrode of the triode Q4 is divided into two paths, one path is connected with the grid electrode of a field effect transistor Q1, and the other.
In fig. 2, 220V ac (for three-phase 380V ac, three sets of controllers are required to be configured) is connected to a piezoresistor Ry1(471) through a fuse BX1 to serve as a lightning protection device. The capacitor C1 is a higher frequency interference absorbing device. The input end of the rectifier bridge ZQ1 is connected with a fuse BX1 through a load, and the other input end is directly connected with 220V commercial power. The output end of the rectifier bridge ZQ1 is connected to a switching tube Q1 (the switching tube may be a field effect transistor or an IGBT, and this embodiment takes a field effect transistor as an example for explanation), a source of a field effect transistor Q1 (for convenience of explanation and understanding, the same label "Q1" as the switching tube is used here) is connected to a negative electrode of the rectifier bridge ZQ1, when a gate of a field effect transistor Q1 has a signal voltage, the field effect transistor Q1 is turned on, the rectifier bridge ZQ1 operates, a load can be electrically operated, and a resistor R1 is a gate discharge resistor of the field effect transistor Q1; resistor R2 is the load current sampling resistor of the power supply line. In the short-circuit protection switch circuit 2, a high-frequency triode Q2-Q4 with the characteristic frequency of more than 100MHz and a resistor R3-R8 form a rapid electronic self-locking switch.
The initial working process of the circuit is that after the power supply is switched on, 220V mains supply is subjected to voltage reduction through a protector BX1 and a transformer B1, and after being filtered by a capacitor C2, the 220V mains supply is connected to a voltage regulator IC1 (a 78M12 voltage regulator is selected) and a voltage regulator IC2 (a 7805 voltage regulator is selected). The voltage stabilizer IC1 outputs +12V stable direct current working voltage to provide power supply for the short-circuit protection circuit 2; voltage regulator IC2 provides a stable +5V dc operating voltage for signal control circuit 3.
As shown in fig. 5, the circuit structure of the signal control circuit 3 is that a single chip IC3 (AT 89S 2051) is used as a core element, an input terminal of a pin P3.3 of the single chip IC3 is connected with an overload detection signal output by the overload detection control circuit, an input terminal of a pin P3.4 of the single chip IC3 is connected with a virtual connection detection signal output by the virtual connection detection protection circuit, an input terminal of a pin P3.5 of the single chip IC3 is connected with a collector of a triode Q6, and a base of the triode Q6 is connected with a short-circuit detection signal output by the short-circuit protection switch circuit through a base resistor R18; the Vcc pin of the singlechip IC3 is connected to the output end of a voltage stabilizer IC2 in the power supply circuit to obtain +5V direct current working voltage, a reset switch AN1 and a capacitor C7 are respectively connected between the Vcc pin and the RST pin of the singlechip IC3, pins P1.4 to P1.7 of the singlechip IC3 are respectively connected with one path of (four paths in total) light emitting diode indicating circuits, and a pin P3.7 of the singlechip IC3 is connected to the negative electrode of the input end of the optical coupler GO1 in the power supply circuit through the QD1 end. The light emitting diodes LED 2-LED 5 in the four light emitting diode indicating circuits are respectively used as an operation indication, a short circuit indication, an overload indication and a virtual connection indication, and the other light emitting diode indicating circuit formed by connecting the light emitting diode LED1 and a resistor R13 in series is used as a power supply indication.
As shown in fig. 5 and 2, the program of the signal control circuit 3 is designed to be automatically started when powered on, after the power is powered on, a pin P3.7 of the single chip microcomputer IC3 outputs a low level to the negative electrode of the input end of the optocoupler GO1 through the end QD1 (fig. 2), the positive electrode of the input end of the optocoupler GO1 is connected to the output end of the voltage regulator IC2 in the power supply circuit through the current limiting resistor R10 to obtain a +5V direct current working voltage, so that the optocoupler GO1 is turned on, and is connected to the base electrode of the triode Q5 through the resistor R11 to turn on the triode Q5, and the gate of the field effect transistor Q1 obtains a signal voltage to be forced to be turned on, so.
When a short-circuit signal (the current rising rate reaches or exceeds 50A/mu S) appears in a load loop, the peak voltage at two ends of the load sampling resistor R2 exceeds 0.7V, the high-speed electronic self-locking switch is immediately locked and conducted, and the locking process is as follows: the voltage at the two ends of the load sampling resistor R2 exceeds 0.7V, the triode Q2 obtains base current through the resistor R3 and is conducted, the triode Q3 is conducted along with the base current, the base current is supplied to the base of the triode Q2 through the resistor R6 and is kept in the state (namely the state of locking conduction) permanently, the triode Q4 is conducted along with the base current, the grid of the field effect tube Q1 is short-circuited to the ground, the field effect tube Q1 is closed, and the closing speed is below 2 mu S. That is, the maximum duration of the short-circuit current, at which the spark cannot be generated, does not exceed 2 μ S.
As shown in fig. 3, the starting current tracking adjustment circuit has a circuit structure that +12V dc power outputted by a regulator IC1 in a power circuit 1 is divided into three paths, a first path is connected with an input terminal of a regulator IC4, a second path is connected with a base of a triode Q7 through a base resistor R22, a third path is connected with a collector of a triode Q7, an output terminal of a regulator IC4 is connected with a voltage division branch formed by connecting resistors R20 and R21 in series, a connection node lead of a resistor R20 and a resistor R21 is connected with an inverting input terminal of an operational amplifier IC5A, a non-inverting input terminal of the operational amplifier IC5A is connected with a differential circuit formed by connecting a resistor R19 and a capacitor C10, one end of a resistor R19 (through an ZA1 terminal) is connected with a short-circuit protection switch circuit, a feedback resistor R23 is connected between an output terminal and the inverting input terminal of the operational amplifier IC5A, an output terminal of the operational amplifier IC5 is divided into three paths, the first path is connected with an overload detection control circuit, the base of the triode, the third path is connected with the base electrode of a triode Q8 through a resistor R27, the emitting electrode of the triode Q8 is grounded, and the collecting electrode of the triode Q8 is connected with a fast electronic self-locking switch in the short-circuit protection switch circuit (through an ZA2 end) after being connected with a resistor R28 in series.
The circuit structure of the overload detection control circuit is that a +12V direct-current power supply output by a voltage stabilizer IC1 in a power supply circuit 1 is grounded after passing through a resistor R24 and a voltage stabilizer DW1, a lead wire is connected with an inverting input end of an operational amplifier IC5B from a connecting node of the resistor R24 and the voltage stabilizer DW1, a non-inverting input end of the operational amplifier IC5B is connected with an output end of an operational amplifier IC5A in a starting current tracking and adjusting circuit through a resistor R26, an output end of the operational amplifier IC5B is connected with a base electrode of a triode Q10 through a resistor R33, a collector electrode of the triode Q10 is connected with a P3.3 pin of a singlechip IC3 in a signal control circuit, an overload detection signal is output to the signal control circuit 3, and an emitter electrode. The collector of a triode Q7 in the starting current tracking and adjusting circuit is grounded through a voltage division circuit consisting of a resistor R30 and a resistor R32, the voltage division node lead of the resistor R30 and the resistor R32 is connected with the base of a triode Q9, the collector of a triode Q9 passes through a resistor R31, one path of the collector is connected to the non-inverting input end of an operational amplifier IC5B, and the other path of the collector is grounded through a capacitor C13.
The starting current tracking and adjusting circuit and the overload detection control circuit can be combined into a whole to form a tracking type overload protection circuit. The protection value of the circuit is determined by the resistance value of the load current sampling resistor R2 in the short-circuit protection switch circuit 2, and is also determined by the operation or rated power of the protected electric appliance. For example, the total power of the electric appliances in a household is 8800W, the rated current is about 40A (the peak current is about 56A), and then the resistance value of the load current sampling resistor R2 is 12.5m Ω and the power is 40W (alternatively, 100m Ω 5W of 8 constantan resistors are connected in parallel). The starting or suspending condition during normal operation can occur at any time, because the starting current is far greater than the running current, when a large current is started (when no short circuit occurs), the current at the upper end (namely the ZA1 end) of the load current sampling resistor R2 is gradually increased, and is connected to the non-inverting input end (pin 3) of the operational amplifier IC5A after the time delay of a differential circuit consisting of a resistor R19 and a capacitor C10, and the voltage stabilizing and dividing circuit (the series circuit of a resistor R20 and a resistor R21) at the inverting input end obtains a constant voltage value of 0.68V by the voltage division of the adjustable voltage regulator IC4 (LM 317), the resistor R20 and the resistor R21; when the voltage at the ZA1 end is delayed by 7 muS and rises to be larger than 0.68V, the circuit of the operational amplifier IC5A is conducted, at the moment, the output end (1 pin) of the operational amplifier IC5A outputs high level, base current is provided for the triode Q8 through the resistor R27, the triode Q8 is conducted, the collector of the triode Q8 is low level, and then the base of the triode Q2 in the rapid electronic self-locking switch is connected through the ends of the resistors R28 and ZA2, so that the rapid electronic self-locking switch is forced to enter a large-current starting mode. If the load is started normally, the starting mode of the starting curve that the current rises rapidly and then falls slowly is necessarily met; because the current of the whole starting process is larger than the running current value and the difference of the length of the current reduction process is larger, a current reduction tracking circuit is designed in the starting current tracking and adjusting circuit. In fig. 3, a current drop tracking circuit is formed by a resistor R25, a capacitor C12 and a transistor Q7. When the load is started, the output end (pin 1) of the operational amplifier IC5A presents high level, and the circuit keeps the running state without overload; when the starting current is in a falling section, the triode Q8 will be out of saturation conduction, the potential of the output end (pin 1) of the operational amplifier IC5A starts to slowly fall, and the capacitor C12 is charged, the charging current can provide base current for the triode Q7, so that the triode Q7 is forced to be in saturation conduction, the triode Q9 is also conducted, and the capacitor C13 is discharged through the resistor R31, so that the potential of the non-inverting input end (pin 5) of the operational amplifier IC5B falls, and the output overload signal is avoided. Only after the current reduction process is finished, it is possible to detect the overload and output an overload signal. The output of the overload signal is completed by a circuit formed by an output end (7 pin) of an operational amplifier IC5B, a capacitor C14, a resistor R33, a resistor R34, a triode Q10 and the like, meanwhile, the overload signal is also connected to a P3.3 pin of a singlechip IC3 in a signal control circuit 3, corresponding LED signal display is carried out by control in the singlechip, and high level is output through the P3.7 pin, so that an optocoupler G01 in a power circuit 1 is cut off (figure 2), the triode Q5 connected with the optocoupler G01 is cut off, a field effect transistor Q1 is cut off due to the loss of signal voltage of a grid, and a rectifier bridge ZQ1 is cut off an alternating current load circuit, thereby realizing overload protection.
As shown in fig. 4, the virtual connection detection protection circuit has a circuit structure that a +12V dc power supply output by a regulator IC1 in a power supply circuit is grounded after one path passes through a resistor R38, a resistor R39 and a capacitor C17 which are connected in series in sequence, the other path is connected with an input end of the regulator IC6, an output end of the regulator IC6 is connected with a voltage dividing circuit composed of a resistor R37 and a resistor R36, a voltage dividing node of the resistor R37 and the resistor R36 is connected to an inverting input end of the operational amplifier IC7, a non-inverting input end of the operational amplifier IC7 is connected to a differential circuit composed of a resistor R35 and a capacitor C15 (through an ZA1 end) to the short-circuit protection switch circuit 2, an output end of the operational amplifier IC7 is connected to a connection node between the resistor R39 and the capacitor C17, a base of a transistor Q11 is connected to a connection node of the resistor R36 38 and the resistor R39, an emitter of a triode Q11 is connected to a +12V dc power supply, a collector of the transistor Q11 is grounded, the 4 feet and the 7 feet of the counter IC8 are respectively connected with a diode (D2, D3) and then are connected with a voltage division circuit consisting of a resistor R43 and a resistor R44 in common, the voltage division node leads of the resistor R43 and the resistor R44 are connected with the base electrode of a triode Q12, one path of the collector electrode of the triode Q12 is connected with a resistor R45 in series and then is connected with a short-circuit protection switch circuit (through an ZA3 end), and the other path of the collector electrode is connected with the P3.4 foot of a singlechip IC3 in the signal control circuit 3 through a diode D4.
In fig. 4, the voltage across the load sampling resistor R2 in the short-circuit protection switch circuit (fig. 2) is connected to the differential circuit composed of the resistor R35 and the capacitor C15 in the virtual connection detection protection circuit 6 through the ZA1 terminal, and then is connected to the non-inverting input terminal (pin 3) of the operational amplifier IC7, and the operating voltage in the normal state is above 0.4V; the inverting input terminal (pin 2) of the operational amplifier IC7 is provided with a constant voltage with a voltage division value of 10mV by the regulator IC6, the resistor R37 and the resistor R36, so that the output terminal (pin 1) of the operational amplifier IC7 is always kept at a high level. When an open circuit and a broken wire occur in an alternating current power supply circuit (the broken wire factors are generally joint corrosion, aging, cracking and the like), transient zero current or micro current can occur, so that zero voltage appears at a non-inverting input end (pin 3) of the operational amplifier IC7, low level appears at an output end (pin 1) of the operational amplifier IC7, at the moment, the PNP triode Q11 can be conducted, a high level appears at a collector of the PNP triode Q11, a high level appears at a pin 14 input end of the counter IC8 (CD 4017), a high level is changed from a high level to a low level at a pin 3 output end, and a high level is changed from a low level to a high level at; when the circuit is connected again, the output end (pin 1) of the operational amplifier IC7 is at a high level, the triode Q11 is cut off, the input end of the pin 14 of the counter IC8 is at a low level, the output of the counter is unchanged, and at the moment, if the circuit is repeatedly disconnected, the virtual connection condition of the circuit can be judged. At this time, the output end of the 4-pin of the counter IC8 is at high level, and the triode Q12 is turned on through the diode D2 and the resistor R43, the collector of the triode Q12 becomes low level, one path of the signal is output to the base (fig. 2) of the triode Q3 in the short-circuit protection switch circuit through the resistor R45 connected in series and the terminal ZA3, the fast electronic self-locking switch is turned on, the field effect transistor Q1 is turned off, and the rectifier bridge ZQ1 is turned off from the alternating current load circuit, thereby realizing virtual connection protection.
Claims (4)
1. A tracking electronic fire protection controller, comprising:
the virtual connection detection protection circuit is respectively connected with the short-circuit protection switch circuit and the signal control circuit and is used for monitoring an open-circuit signal of an electrical appliance or a power supply line and sending a virtual connection power-off signal to the short-circuit protection switch circuit and the signal control circuit when the virtual connection condition is judged to occur;
the overload detection control circuit is respectively connected with the short-circuit protection switch circuit and the signal control circuit and is used for monitoring the overcurrent or local short-circuit condition of the electrical appliance and sending an overload power-off signal to the short-circuit protection switch circuit and the signal control circuit when judging that the overload condition occurs;
the short-circuit protection switch circuit is respectively connected with the virtual connection detection protection circuit, the overload detection control circuit, the signal control circuit and the power circuit and is used for disconnecting the power circuit through the rapid electronic self-locking switch circuit when short-circuit, virtual connection or overload occurs to an electric appliance and a power supply line;
the starting current tracking and adjusting circuit is connected with the signal control circuit and is used for tracking the starting current of the electric appliance and correspondingly adjusting the protection value along with the change of the starting current;
the signal control circuit is respectively connected with the virtual connection detection protection circuit, the overload detection control circuit, the short-circuit protection switch circuit and the starting current tracking and adjusting circuit and is used for indicating the instant states of the electric appliance and the power supply line; and
the power supply circuit provides alternating current working voltage for a load and provides direct current working voltage for each part of circuits;
the short-circuit protection switch circuit is formed by connecting an input end of a rectifier bridge ZQ1 on one power line connected with an alternating current output end, the cathode of the output end of the rectifier bridge ZQ1 is grounded, the anode of the output end is connected with the input electrode of a switch tube Q1, the control electrode of the switch tube Q1 is connected with a resistor R9 in a power circuit, the output electrode of a switch tube Q1 is divided into three paths, the first path is grounded through a load current sampling resistor R2, the second path is connected with a connecting terminal ZA1 for tapping an overload detection control circuit and a virtual connection detection protection circuit, the third path is connected with the base electrode of a triode Q2 through a resistor R3, the collector electrode of the triode Q2 is connected with the +12V direct current voltage output end of the power circuit through a resistor R4 and a resistor R5 which are connected in series to obtain a +12V direct current working voltage, a lead is connected to the connecting node of the resistor R4 and the resistor R5, one path is connected with a connecting, the other circuit is connected with the base electrode of a triode Q3, the emitter electrode of a triode Q3 is connected with the +12V direct-current voltage output end of a power circuit, the collector electrode of a triode Q3 is divided into three circuits, the first circuit is connected with a connecting terminal ZA2 used for being connected with an overload detection control circuit through a resistor R6, the second circuit is connected with a resistor R18 in a signal control circuit so as to output a short-circuit signal to the signal control circuit, the third circuit is grounded through a resistor R7 and a resistor R8, the base electrode of a triode Q4 is connected with a lead on the connecting node of a resistor R7 and a resistor R8, the emitter electrode of a triode Q4 is grounded, the collector electrode of a triode Q4 is divided into two circuits, one circuit is connected with the control electrode of a switching tube Q.
2. The tracking electronic fire-proof controller as claimed in claim 1, wherein the power circuit is configured such that an ac input terminal is connected to an ac output terminal through a fuse BX1, a capacitor C1 and a varistor Ry1 are connected in parallel between two terminals of the ac input terminal, a primary side of a transformer B1 is connected to the two terminals of the ac input terminal by a lead wire, a negative side of the transformer B1 is divided into two paths after passing through a rectifier bridge ZQ2 and a filter capacitor C2, one path is connected to an input terminal of a regulator IC1, a +12V dc operating voltage is output from the regulator IC1, the other path is connected to an input terminal of a regulator IC2, and a +5V dc operating voltage is output from the regulator IC 2; the output of stabiliser IC1 is behind filter capacitor C3 and electric capacity C4, be connected to triode Q5's projecting pole, stabiliser IC 2's output is behind filter capacitor C5 and electric capacity C6, series connection resistance R10, it is anodal to be reconnected to opto-coupler GO 1's input, opto-coupler GO 1's input negative pole connects signal control circuit, opto-coupler GO 1's output negative pole ground connection, the base of triode Q5 is received through base resistance R11 to opto-coupler GO 1's output positive pole, triode Q5's collecting electrode connects triode Q4's in the short-circuit protection switch circuit through resistance R9.
3. The tracking electronic fire-proof controller as claimed in claim 2, wherein the signal control circuit is configured to take the one-chip microcomputer IC3 as a core component, the P3.3 pin input terminal of the one-chip microcomputer IC3 is connected to the overload detection signal output by the overload detection control circuit, the P3.4 pin input terminal of the one-chip microcomputer IC3 is connected to the virtual connection detection signal output by the virtual connection detection protection circuit, the P3.5 pin input terminal of the one-chip microcomputer IC3 is connected to the collector of the triode Q6, and the base of the triode Q6 is connected to the short-circuit detection signal output by the short-circuit protection switch circuit through the base resistor R18; the Vcc pin of the singlechip IC3 is connected to the output end of a voltage stabilizer IC2 in the power supply circuit to obtain +5V direct current working voltage, a reset switch AN1 and a capacitor C7 are respectively connected between the Vcc pin and the RST pin of the singlechip IC3, pins P1.4 to P1.7 of the singlechip IC3 are respectively connected with a light emitting diode indicating circuit, and a pin P3.7 of the singlechip IC3 is connected with the negative electrode of the input end of AN optical coupler GO1 in the power supply circuit.
4. The tracking electronic fire-proof controller according to claim 3, wherein the virtual connection detection protection circuit is composed of a +12V DC power supply output by a voltage stabilizer IC1 in a power supply circuit, one path is grounded through a resistor R38, a resistor R39 and a capacitor C17 which are connected in series in sequence, the other path is connected with the input end of a voltage stabilizer IC6, the output end of the voltage stabilizer IC6 is connected with a voltage dividing circuit composed of a resistor R37 and a resistor R36, the voltage dividing node of the resistor R37 and the resistor R36 is connected to the inverting input end of the operational amplifier IC7, the non-inverting input end of the operational amplifier IC7 is connected in series with a resistor R35 and then connected with a connecting terminal ZA1 for connecting a short-circuit, the output end of the operational amplifier IC7 is connected to the connecting node between the resistor R39 and the capacitor C17, the base of the triode Q11 is connected to the connecting node of the resistor R38 and the resistor R39, the emitter of the triode Q11 is connected with the +12V DC power supply, and the collector, the other path is connected with a pin 14 of a counter IC8 through a resistor R41, a pin 4 and a pin 7 of the counter IC8 are respectively connected with a diode and then are commonly connected with a voltage division circuit consisting of a resistor R43 and a resistor R44, voltage division node leads of the resistor R43 and a resistor R44 are connected to a base electrode of a triode Q12, one path of a collector of the triode Q12 is connected with a resistor R45 in series and then is connected with a connecting terminal ZA3 used for connecting a short-circuit protection switch circuit, and the other path is connected with a pin P3.4 of a singlechip IC3 in a signal control circuit through a diode D4.
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| CN110350899A (en) * | 2019-08-09 | 2019-10-18 | 广东福田电器有限公司 | Noncontacting switch |
| CN114995253A (en) * | 2022-06-24 | 2022-09-02 | 山东创典智能科技有限公司 | Programmable high-speed multi-station multi-target online position tracking monitoring controller |
| TWI856543B (en) * | 2023-03-06 | 2024-09-21 | 達擎股份有限公司 | Electronic device and start-up control system |
| CN120703638A (en) * | 2025-08-21 | 2025-09-26 | 北海通信(深圳)集团有限公司 | A load detection circuit for a digital power amplifier |
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| CN2059774U (en) * | 1989-06-26 | 1990-07-25 | 张玉敏 | Power failure self-cut-off device |
| CN2342509Y (en) * | 1998-06-29 | 1999-10-06 | 胡新锁 | Anti-fire protector for AC loop |
| CN102130439A (en) * | 2011-03-16 | 2011-07-20 | 天津市鸿远电气设备有限公司 | Leakage protection switch with virtual connection preventing function |
| JP5906679B2 (en) * | 2011-11-10 | 2016-04-20 | 富士電機株式会社 | Power converter and overcurrent protection circuit |
| CN203660494U (en) * | 2013-12-25 | 2014-06-18 | 上海第二工业大学 | Device for realizing quick broken circuit protection in alternating-current circuit by using single IGBT tube |
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