Control device and control method for voltage fault protection

Abstract

The invention relates to a control device and control method for voltage fault protection, and belongs to the technical field of power equipment. The device comprises a single-chip microcomputer main control circuit module, a power supply circuit module, an input voltage acquisition circuit module, an output voltage feedback acquisition circuit module, a relay driving circuit module, an operation key module and an indicating lamp module. According to the invention, overvoltage and undervoltage protection of the control device for voltage fault protection on the voltage is realized; the function of automatically recovering power supply when the voltage is recovered to a normal range is realized; an emergency power utilization function is realized; a locking function is realized, and load impact caused by frequent opening and closing is avoided; the fault self-diagnosis function of the relay loop is realized; the upper limit of the power supply voltage adaptation range is expanded; the optimization of the voltage acquisition circuit and the optimization of the relay driving circuit are realized. According to the invention, the complexity of the circuit is reduced, reliable long-time work is ensured, and the reliability is improved.

Description

Technical field[0001]The present invention relates to a control device and a control method of voltage fault protection, belonging to the technical field of power equipment.Background technique[0002]When the neutral line in the distribution line fails, the supply line itself voltage is unstable, the circuit load working circuit is too large, the power supply line is short-circuited, the transformer capacity is less than or even fault, the electrical line may have an undervoltage. If there is an undervoltage failure, the circuit breaker does not make timely protection, which may cause damage to the equipment, and even cause a fire. When the circuit breaker protects the trip, if the hand is used, the user cannot accurately understand the recovery of the voltage, the blind manual closing is unsafe is inconvenient, and may result in secondary harm. Traditional overvoltage protector is generally implemented by the microcirculator side of the undervoltage trip module. This type of spellin...

AI Technical Summary

Problems solved by technology

[0003] The power supply input voltage range specified in the self-resetting overvoltage and undervoltage product standards is relatively wide, especially when the protector works in the high voltage range, the withstand voltage requirements for the capacitor are high, and the capacity of the capacitor will increase with the long-term use of the product And the drift affects the output capability of the power supply

For example, the power supply circuit used in the Chinese patent document CN103311884B adopts a resistance-capacitance step-down scheme. When the input voltage is high, such as 440VAC, the resistance will heat up, and the capacitance of the capacitance will not be able to withstand the voltage enough, so it cannot work reliably for a long time.

The driving circuit of the magnetic latching relay used in the Chinese patent document CN205945016U patent requires 6 switching devices plus 4 control pins to cooperate to complete the control of the relay, which will make the circuit more complicated and increase unreliability

In the voltage detection circuit used in the Chinese patent document CN103311884B patent, after the input voltage is stepped down by a resistor, the voltage signal is differentially amplified, and then input to the single-chip microcomputer for AD detection. This method has many circuit components and increases the complexity. degree, also introduces more factors that affect the measurement error

The overvoltage and undervoltage comparison scheme used in the Chinese patent document CN203026906U uses a hysteresis comparator circuit, which has low voltage accuracy and is greatly affected by the ambient temperature.

In the voltage sampling circuit used in the Chinese patent document CN108471104A, the input voltage is stepped down and then half-wave rectified. The forward voltage drop deviation of the D6 diode will be different due to device differences and temperature drift, which will affect to a large extent Voltage Sampling Accuracy

In addition, in the existing voltage protection circuit breaker products, if the overvoltage and undervoltage protection occurs, but the voltage has not fully recovered to the normal voltage range that can automatically close the switch, the protector will not close.

In this way, in some maintenance or emergency occasions, emergency power supply cannot be performed.

In the existing voltage protection circuit breaker products, there is a lack of monitoring of the state of the relay contacts, and unreliable opening and closing will cause harm to the operators and equipment of the subsequent circuit

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