A power frequency voltage zero-crossing monitoring and protection tripping circuit

Abstract

The utility model discloses a kind of power frequency voltage zero-crossing monitoring and protection opening circuit, including zero-crossing monitoring circuit, precision sampling circuit, opening control circuit and single-chip microcontroller, the zero-crossing monitoring circuit, precision sampling circuit, opening control circuit are electrically connected with single-chip microcontroller The precision sampling circuit and single-chip microcontroller I2C interface are connected, the zero-crossing monitoring circuit and the input port of single-chip microcontroller are electrically connected, the output port of single-chip microcontroller and opening control circuit are electrically connected;The utility model can realize power frequency voltage zero-crossing monitoring using only a small amount of discrete components, and realize voltage zero point vicinity trip under overload and other fault conditions, reduce the energy of arc when switch is opened, prolong the mechanical and electrical life of switch device.

Description

Technical Field

[0001] This utility model belongs to the field of power equipment technology, specifically relating to a power frequency voltage zero-crossing monitoring and protection circuit. Background Technology

[0002] With the accelerated advancement of power system intelligence, power frequency quantity acquisition and protection tripping technology have become core supports for modern power grid security defense systems. This technology, by monitoring the phase, amplitude, and other characteristic parameters of power frequency signals in real time, can quickly identify abnormal operating conditions such as line short circuits and grounding faults. Combined with protection devices, it can achieve precise isolation of fault areas, effectively preventing the spread of faults. Especially under the large-scale grid integration of new energy sources and AC / DC hybrid power grid architectures, accurate acquisition of power frequency quantities plays a crucial role in transient process analysis, harmonic suppression, and system stability control, and is an important technical means to ensure the safe operation of ultra-high voltage transmission corridors and the reliable power supply of urban distribution networks.

[0003] However, existing power frequency quantity acquisition and protection tripping technologies still suffer from significant technical bottlenecks. Traditional solutions generally employ an "AD chip + microcontroller" architecture for zero-crossing detection. This hardware system has inherent defects such as accumulated sampling and quantization errors and insufficient clock synchronization accuracy, leading to significant time deviations in zero-crossing point identification. At the algorithm level, existing technologies rely on complex calculations such as Fourier transforms and Kalman filtering to eliminate harmonic interference, which not only increases processing delays but also easily leads to misjudgments in environments with strong electromagnetic interference. These technical shortcomings make existing systems difficult to adapt to the complex operating conditions brought about by a high proportion of new energy integration, and prone to protection delays or malfunctions when the grid transient process changes rapidly.

[0004] Therefore, there is an urgent need for a circuit that can solve the above problems. Utility Model Content

[0005] This invention overcomes the shortcomings of the prior art and provides a power frequency voltage zero-crossing monitoring and protection circuit. This invention can achieve power frequency voltage zero-crossing monitoring with only a few discrete components, and can trip near the voltage zero point in the event of overload or other faults, reducing the energy of the electric arc when the switch is disconnected and extending the mechanical and electrical life of the switching equipment.

[0006] The technical solution adopted by this utility model to solve its existing problems is:

[0007] A power frequency voltage zero-crossing monitoring and protection circuit includes a zero-crossing monitoring circuit, a precision sampling circuit, a circuit breaking control circuit, and a microcontroller. The zero-crossing monitoring circuit, the precision sampling circuit, and the circuit breaking control circuit are all electrically connected to the microcontroller.

[0008] The precision sampling circuit is connected to the microcontroller's I2C interface for communication, the zero-crossing monitoring circuit is electrically connected to the microcontroller's input port, and the microcontroller's output port is electrically connected to the trip control circuit.

[0009] Preferably, the zero-crossing monitoring circuit includes diodes D1 and D2, resistors R1, R2, R3, R4 and R5, capacitors C1, C2, C3, C4 and C5, Zener diode ZD1, NPN transistor Q1, and optocoupler E1.

[0010] Preferably, the zero-crossing monitoring circuit specifically comprises:

[0011] The positive terminal of diode D1 is connected to phase A voltage Ua, and the negative terminal of diode D1 is connected to resistors R1 and R2 in sequence. The output terminal of resistor R2 is electrically connected to the anode A port of optocoupler E1.

[0012] The zero-crossing monitoring circuit is also equipped with a common terminal Un for phase A voltage. Specifically, capacitor C3 and resistor R3 are connected in parallel, with one end connected to the anode A port of optocoupler E1 and the other end connected to the common terminal Un for phase A voltage.

[0013] The capacitor C4 and the Zener diode ZD1 are connected in parallel. One end is connected to the anode A port of the optocoupler E1, and the other end is electrically connected to the emitter E port of the NPN transistor Q1 and electrically connected to the positive terminal of the diode D2. The negative terminal of the diode D2 is connected to the common terminal Un of the A-phase voltage.

[0014] The common terminal Un of phase A is electrically connected in sequence to resistor R4 and the base B port of NPN transistor Q1. The collector C port of NPN transistor Q1 is electrically connected to the cathode K port of optocoupler E1. A capacitor C2 is electrically connected between the base B port and the emitter E port of NPN transistor Q1.

[0015] The collector (C) port of the optocoupler E1 is connected to the VDD terminal on one side and to the ground terminal on the other side via capacitor C1. The emitter (E) port of the optocoupler E1 is electrically connected to two branches: one branch connects to resistor R5 and capacitor C5 in parallel and is connected to the ground terminal; the other branch connects to the microcontroller.

[0016] Preferably, the precision sampling circuit includes a current transformer CT1, resistors R6 and R7, capacitor C6, bidirectional TVS diode D3, and AD acquisition chip.

[0017] Preferably, the precision sampling circuit specifically comprises:

[0018] The primary side port of the current transformer CT1 is connected to the A-phase current Ia and the common terminal In of the A-phase current, respectively. The secondary side port 3 of the current transformer CT1 has two branches. One branch is connected to the resistor R6 and then electrically connected to the secondary side port 4 of the current transformer CT1. The other branch is electrically connected to one end of the resistor R7. The other end of the resistor R7 is connected to one end of the capacitor C6 and the TVS diode D3. The capacitor C6 and the TVS diode D3 are connected in parallel. The other end of the capacitor C6 and the TVS diode D3 is connected to the secondary side port 4 of the current transformer CT1 and then connected to the ground terminal.

[0019] The output terminal of resistor R7 and the secondary side 4 port of current transformer CT1 are electrically connected to the AD acquisition chip, which is electrically connected to the microcontroller.

[0020] Preferably, the tripping control circuit includes resistors R8, R9, R10, and R11, an optocoupler E2, a diode D4, an NMOS transistor Q2, a relay K1, and a tripping output J1.

[0021] Preferably, the tripping control circuit specifically comprises:

[0022] The enable port and control port of the microcontroller are electrically connected to the trip control circuit. The enable port is electrically connected to resistor R10 and then splits into two branches. One branch is connected to the gate (G) port of NMOS transistor Q2, and the other branch is connected in sequence to resistor R11 and the source (S) port of NMOS transistor Q2 and then connected to the ground terminal.

[0023] The control port is divided into two branches. One branch is connected to the VDD terminal via resistor R9, and the other branch is connected to the cathode K port of optocoupler E2. The anode A port of optocoupler E2 is connected to resistor R8 and then to the VDD terminal. The collector C port of optocoupler E2 is connected to the VCC terminal.

[0024] The emitter E port of the optocoupler E2 is electrically connected to port 1 of the relay K1. Port 2 of the relay K1 is connected to the anode of diode D4 and the drain D port of NMOS transistor Q2. The cathode of diode D4 is connected to the emitter E port of the optocoupler E2. Ports 8 and 5 of the relay K1 are connected to the trip output J1.

[0025] Preferably, the enable port and control port of the microcontroller are specifically the output ports of the microcontroller.

[0026] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0027] Compared to existing power frequency quantity acquisition and protection tripping circuits, this invention uses a zero-crossing monitoring circuit to convert the zero-crossing point of the power frequency voltage into a pulse signal, which is then transmitted to the microcontroller. A precision sampling circuit transmits the power frequency current signal to the microcontroller, which analyzes this signal to determine if an electrical fault has occurred. If the microcontroller determines a fault has occurred, it combines the zero-crossing pulse signal from the zero-crossing monitoring circuit with the pulse signal it receives. Upon acquiring the pulse signal, the microcontroller synchronously drives the tripping control circuit, causing the circuit breaker to trip via the tripping output. This quickly disconnects the fault without generating significant arc energy, ensuring stable operation of the power system. The zero-crossing monitoring circuit uses simple discrete components and involves no software, effectively converting the zero-crossing point of the power frequency quantity into a pulse signal easily recognizable by the microcontroller. It is low-cost, highly reliable, and works effectively with the precision sampling circuit and tripping control circuit to achieve zero-crossing monitoring and protection functions. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] Figure 1 This is a schematic diagram of the electrical connection of a power frequency voltage zero-crossing monitoring and protection tripping circuit according to the present invention.

[0030] Figure 2 This is a detailed structural diagram of a power frequency voltage zero-crossing monitoring and protection circuit of the present invention. Detailed Implementation

[0031] The specification and claims use certain terms to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error.

[0032] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] The attached figure shows the preferred embodiment of the power frequency voltage zero-crossing monitoring and protection circuit. The present invention will be further described in detail below with reference to the attached figure.

[0035] A power frequency voltage zero-crossing monitoring and protection circuit includes a zero-crossing monitoring circuit, a precision sampling circuit, a circuit breaking control circuit, and a microcontroller. The zero-crossing monitoring circuit, the precision sampling circuit, and the circuit breaking control circuit are all electrically connected to the microcontroller.

[0036] The precision sampling circuit communicates with the microcontroller's I2C interface, transmitting the current analog signal to the microcontroller in real time. The zero-crossing monitoring circuit is electrically connected to the microcontroller's input port, and the microcontroller's output port is electrically connected to the trip control circuit.

[0037] The zero-crossing monitoring circuit includes diodes D1 and D2, resistors R1, R2, R3, R4 and R5, capacitors C1, C2, C3, C4 and C5, Zener diode ZD1, NPN transistor Q1, and optocoupler E1.

[0038] The zero-crossing monitoring circuit is specifically as follows:

[0039] The anode of diode D1 is connected to the phase A voltage Ua, and the cathode of diode D1 is connected in sequence to resistors R1 and R2. The output terminal of resistor R2 is electrically connected to the anode A port of optocoupler E1. The zero-crossing monitoring circuit also has a phase A voltage common terminal Un. Specifically, capacitor C3 and resistor R3 are connected in parallel, with one end connected to the anode A port of optocoupler E1 and the other end connected to the phase A voltage common terminal Un.

[0040] The capacitor C4 and the Zener diode ZD1 are connected in parallel. One end is connected to the anode A port of the optocoupler E1, and the other end is electrically connected to the emitter E port of the NPN transistor Q1 and electrically connected to the positive terminal of the diode D2. The negative terminal of the diode D2 is connected to the common terminal Un of the A-phase voltage.

[0041] The common terminal Un of phase A is electrically connected in sequence to resistor R4 and the base B port of NPN transistor Q1. The collector C port of NPN transistor Q1 is electrically connected to the cathode K port of optocoupler E1. A capacitor C2 is electrically connected between the base B port and the emitter E port of NPN transistor Q1.

[0042] The collector (C) port of the optocoupler E1 is electrically connected to two branches: one branch connects to capacitor C1 and ground in sequence, and the other branch connects to VDD. The emitter (E) port of the optocoupler E1 is electrically connected to two branches: one branch connects to resistor R5 and capacitor C5, which are connected in parallel and then to ground; the other branch connects to the microcontroller.

[0043] The working principle of the zero-crossing monitoring circuit is as follows:

[0044] During the positive half-wave of the power frequency voltage Ua, capacitor C4 is primarily charged and stores energy. The charging path of capacitor C4 starts from the power frequency voltage Ua terminal, passes through diode D1, resistor R1, resistor R2, capacitor C4, and diode D2 to the power frequency voltage Un. Diodes D1 and D2 act as rectifiers, while resistors R1 to R3 act as voltage dividers and current limiters. Capacitor C3, with its smaller capacitance, primarily filters out high-frequency interference from the power frequency voltage. Zener diode ZD1 ensures that the maximum charging voltage of capacitor C4 remains stable below a specified value.

[0045] After the power frequency voltage Ua transitions from the positive half-wave to the negative half-wave, the circuit primarily drives the optocoupler E1 to output a high-level zero-crossing monitoring signal. At this time, the current flow path is sequentially: power frequency voltage Un, resistor R4, base port B and emitter port E of NPN transistor Q1, and capacitor C4. Simultaneously, NPN transistor Q1 is turned on, and the charge stored in capacitor C4 flows through capacitor C4, anode port A and cathode port K of optocoupler E1, collector port C and emitter port E of NPN transistor Q1, and capacitor C4.

[0046] When current flows through the primary side ports A and K of optocoupler E1, the secondary side ports C and E of optocoupler E1 are turned on, and the zero-crossing monitoring signal is pulled up from low to high. When the charge stored in capacitor C4 is released, no current flows through the primary side ports A and K of optocoupler E1. At this time, the secondary side ports C and E of optocoupler E1 are turned off, and the zero-crossing monitoring signal is pulled down from high to low, generating a zero-crossing pulse signal and transmitting it to the microcontroller. The microcontroller is connected via an I / O port, and the microcontroller determines the zero-crossing time of the AC quantity by monitoring the rising edge of the pulse.

[0047] The functions of capacitors C2, C5, and C1 are to filter out high-frequency interference. Resistor R4 is used to limit the current at the base B port of NPN transistor Q1. The function of resistor R5 is to pull down the zero-crossing monitoring pulse signal so that the output is low by default when optocoupler E1 is turned off.

[0048] The precision sampling circuit includes a current transformer CT1, resistors R6 and R7, capacitor C6, bidirectional TVS diode D3, and AD acquisition chip.

[0049] The precision sampling circuit is specifically as follows:

[0050] The current transformer CT1 has two branches at its 1 and 2 ports connected to the phase A current Ia and the phase A current common terminal In, respectively. The current transformer CT1 has two branches at its 3 port. One branch is connected to the resistor R6 and then electrically connected to the current transformer CT1 at its 4 port. The other branch is electrically connected to one end of the resistor R7. The other end of the resistor R7 is connected to one end of the capacitor C6 and the TVS diode D3. The capacitor C6 and the TVS diode D3 are connected in parallel. The other ends of the capacitor C6 and the TVS diode D3 are connected to the current transformer CT1 at its 4 port and then to the ground terminal.

[0051] The 1, 2, 3, and 4 ports of the aforementioned current transformer CT1 are the primary side input terminal, the primary side output terminal, the secondary side input terminal, and the secondary side output terminal, respectively.

[0052] The output terminal of resistor R7 and the 4-port of current transformer CT1 are electrically connected to the AD acquisition chip, which is electrically connected to the microcontroller.

[0053] The working principle of the precision sampling circuit is as follows:

[0054] The current signal Ia is converted into a small current signal by the current transformer CT1. This current then passes through resistor R6 and is converted into a small voltage signal. This voltage signal is filtered by a low-pass filter composed of resistor R7 and capacitor C6 to remove high-frequency interference before being transmitted to the AD acquisition chip for analog-to-digital conversion. The AD acquisition chip transmits the converted digital information from the current signal Ia to the microcontroller, which analyzes and processes the data to determine if a fault such as current overload has occurred. The TVS diode D3 clamps the input voltage of the AD acquisition chip to prevent the input voltage level from exceeding its tolerance range due to excessive current Ia.

[0055] The tripping control circuit includes resistors R8, R9, R10, and R11, optocoupler E2, diode D4, NMOS transistor Q2, relay K1, and tripping output J1.

[0056] The specific circuit for tripping control is as follows:

[0057] The enable port and control port of the microcontroller are electrically connected to the trip control circuit respectively; the enable port is electrically connected to resistor R10 and then splits into two branches, one of which is connected to the gate G port of NMOS transistor Q2, and the other is connected to resistor R11 and the source S port of NMOS transistor Q2 in sequence and connected to the ground terminal.

[0058] The control port is divided into two branches. One branch is connected to the VDD terminal after connecting to the resistor R9, and the other branch is connected to the cathode K port of the optocoupler E2. The anode A port of the optocoupler E2 is connected to the resistor R8 and then to the VDD terminal. The collector C port of the optocoupler E2 is connected to the VCC terminal.

[0059] The emitter E port of the optocoupler E2 is electrically connected to port K1 of the relay. Port 2 of the relay K1 is connected to the anode of diode D4 and the drain D port of NMOS transistor Q2. The cathode of diode D4 is connected to the emitter E port of the optocoupler E2. Ports 8 and 5 of the relay K1 are connected to the tripping output J1. The enable and control ports of the microcontroller are specifically the output ports of the microcontroller. The tripping enable port is connected to the microcontroller's I / O pin, and the microcontroller enables tripping control by outputting a high-level signal. The tripping output control port is connected to the microcontroller's I / O pin, and the microcontroller drives the tripping output by outputting a low-level signal. Ports 1 and 2 of the relay K1 are specifically two coil ports, and ports 8 and 5 of the relay K1 are specifically dry contacts. When the coils in ports 1 and 2 are energized, the pins in ports 5 and 8 are closed; when the coils in ports 1 and 2 are not energized, the pins in ports 5 and 8 are open.

[0060] The specific working principle of the trip control circuit is as follows:

[0061] When the microcontroller detects a fault such as current overload, it issues a trip signal upon detecting a zero-crossing pulse signal. First, the microcontroller sends a high-level trip control enable signal, driving NMOS transistor Q2 to conduct. Then, the microcontroller sends a low-level trip output control signal, driving optocoupler E2 to conduct. After the relay K1 coil is energized, the dry contacts at ports 5 and 8 activate, connecting to the trip output terminal J1. A trip signal is then sent out through terminal J1, driving the circuit breaker to trip. Resistors R8 to R11 limit current and divide voltage. Resistors R9 and R11 simultaneously act as pull-up and pull-down resistors, ensuring that optocoupler E2 and NMOS transistor Q2 are off by default when there is no trip control signal. Diode D4 provides freewheeling current, preventing voltage spikes in the relay coil when the power supply current is interrupted, which could damage the relay.

[0062] In the diagram, GND represents the neutral wire. GND means common terminal, or ground, but this ground is not the actual earth; it is an assumed ground for application purposes, providing a potential reference for other nodes.

[0063] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A power frequency voltage zero-crossing monitoring and protection tripping circuit, characterized in that, It includes a zero-crossing monitoring circuit, a precision sampling circuit, a tripping control circuit, and a microcontroller. The zero-crossing monitoring circuit, the precision sampling circuit, and the tripping control circuit are all electrically connected to the microcontroller. The precision sampling circuit is connected to the microcontroller's I2C interface for communication, the zero-crossing monitoring circuit is electrically connected to the microcontroller's input port, and the microcontroller's output port is electrically connected to the trip control circuit.

2. The power frequency voltage zero-crossing monitoring and protection circuit according to claim 1, characterized in that, The zero-crossing monitoring circuit includes diodes D1 and D2, resistors R1, R2, R3, R4 and R5, capacitors C1, C2, C3, C4 and C5, Zener diode ZD1, NPN transistor Q1, and optocoupler E1.

3. The power frequency voltage zero-crossing monitoring and protection circuit according to claim 2, characterized in that, The zero-crossing monitoring circuit is specifically as follows: The positive terminal of diode D1 is connected to phase A voltage Ua, and the negative terminal of diode D1 is connected to resistor R1 and resistor R2 in sequence. The output terminal of resistor R2 is electrically connected to the anode A port of optocoupler E1. The zero-crossing monitoring circuit is also equipped with a common terminal Un for phase A voltage. Specifically, capacitor C3 and resistor R3 are connected in parallel, with one end connected to the anode A port of optocoupler E1 and the other end connected to the common terminal Un for phase A voltage. The capacitor C4 and the Zener diode ZD1 are connected in parallel. One end is connected to the anode A port of the optocoupler E1, and the other end is electrically connected to the emitter E port of the NPN transistor Q1 and electrically connected to the positive terminal of the diode D2. The negative terminal of the diode D2 is connected to the common terminal Un of the A phase voltage. The common terminal Un of phase A is electrically connected in sequence to resistor R4 and the base B port of NPN transistor Q1. The collector C port of NPN transistor Q1 is electrically connected to the cathode K port of optocoupler E1. A capacitor C2 is electrically connected between the base B port and the emitter E port of NPN transistor Q1. The collector C port of the optocoupler E1 is connected to the VDD terminal on one side and to the ground terminal through the capacitor C1 on the other side; the emitter E port of the optocoupler E1 is electrically connected to two branches, one of which is connected to the resistor R5 and the capacitor C5 in parallel and connected to the ground terminal, and the other is connected to the microcontroller.

4. The power frequency voltage zero-crossing monitoring and protection circuit according to claim 1, characterized in that, The precision sampling circuit includes a current transformer CT1, resistors R6 and R7, capacitor C6, bidirectional TVS diode D3, and AD acquisition chip.

5. The power frequency voltage zero-crossing monitoring and protection circuit according to claim 4, characterized in that, The precision sampling circuit is specifically as follows: The primary side port of the current transformer CT1 is connected to the A-phase current Ia and the common terminal In of the A-phase current respectively. The secondary side port 3 of the current transformer CT1 has two branches. One branch is connected to the resistor R6 and then electrically connected to the secondary side port 4 of the current transformer CT1. The other branch is electrically connected to one end of the resistor R7. The other end of the resistor R7 is connected to one end of the capacitor C6 and the TVS tube D3. The capacitor C6 and the TVS tube D3 are connected in parallel. The other end of the capacitor C6 and the TVS tube D3 is connected to the secondary side port 4 of the current transformer CT1 and then connected to the ground terminal. The output terminal of resistor R7 and the secondary side 4 port of current transformer CT1 are electrically connected to the AD acquisition chip, which is electrically connected to the microcontroller.

6. The power frequency voltage zero-crossing monitoring and protection circuit according to claim 1, characterized in that, The tripping control circuit includes resistors R8, R9, R10, and R11, optocoupler E2, diode D4, NMOS transistor Q2, relay K1, and tripping output J1.

7. The power frequency voltage zero-crossing monitoring and protection circuit according to claim 6, characterized in that, The specific circuit for tripping control is as follows: The enable port and control port of the microcontroller are electrically connected to the trip control circuit respectively; the enable port is electrically connected to resistor R10 and then splits into two branches, one of which is connected to the gate G port of NMOS transistor Q2, and the other is connected to resistor R11 and the source S port of NMOS transistor Q2 in sequence and connected to the ground terminal. The control port is divided into two branches. One branch is connected to the VDD terminal after connecting to the resistor R9, and the other branch is connected to the cathode K port of the optocoupler E2. The anode A port of the optocoupler E2 is connected to the resistor R8 and then to the VDD terminal. The collector C port of the optocoupler E2 is connected to the VCC terminal. The emitter E port of the optocoupler E2 is electrically connected to the relay K1 port. The relay K1 port 2 is connected to the positive terminal of diode D4 and the drain D port of NMOS transistor Q2. The negative terminal of diode D4 is connected to the emitter E port of optocoupler E2. The relay K1 ports 8 and 5 are connected to the trip output J1.

8. The power frequency voltage zero-crossing monitoring and protection circuit according to claim 7, characterized in that, The enable port and control port of the microcontroller are specifically the output ports of the microcontroller.

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