CN204945235U - A kind of AC voltage sampling circuit - Google Patents

Abstract

The utility model relates to an AC voltage acquisition circuit. The circuit is composed of power transformer T, safety capacitor XC, varistor RV, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, capacitor C1, capacitor C2, and the power transformer T pin 1 Connect with one end of resistor R1 and then connect with safety capacitor XC and one end of varistor RV; connect pin 2 of power transformer T with one end of resistor R2 and then connect with safety capacitor XC and varistor RV connected; pin 3 of power transformer T is connected to resistor R3, resistor R4, and resistor R6; pin 4 of power transformer T is connected to resistor R3, the other end of resistor R4 and one end of resistor R5; the other end of resistor R5, resistor The other end of R6 is connected to one end of capacitor C1 and capacitor C2 respectively. The utility model has double protection functions, and the circuit signal communicates stably.

Description

An AC voltage acquisition circuit

technical field

The utility model relates to the technical field of sensing data acquisition, in particular to an AC voltage acquisition circuit.

Background technique

At present, there are various acquisition circuits for mains voltage on the market, but the basic methods are similar. First of all, the AC voltage is converted from a high-voltage signal to a low-voltage AC signal, then the signal is converted by the conditioning circuit, and finally the required voltage signal is collected through the AD. Part of the existing method is to use a transformer to reduce the high voltage to a low voltage, and then perform calculation processing. The advantage of this method is that it plays the role of isolation protection, but it has the disadvantages of large error, high cost, and high manufacturing cost of the circuit board; The method of resistive voltage division directly converts high-voltage signals into low-voltage signals, and then undergoes conditioning by various unit circuits, such as AD acquisition circuits. However, AD acquisition needs to be isolated from the CPU to communicate safely. Although this solves the problem of large size, the cost is still high, the circuit is easy to be broken down, and the overall circuit design is also relatively cumbersome.

Utility model content

What the utility model aims to solve is to provide an AC voltage acquisition circuit for the technical problems of large error, large volume, easy breakdown and high cost in the existing commercial AC voltage acquisition. Its main feature is that the circuit design is simple , high precision and good stability.

The technical problem to be solved by the utility model can be realized through the following technical solutions:

A mains AC voltage acquisition circuit, first pass the input AC voltage signal through double protection through filtering and then divide it by resistance, and then use a high-precision current-type voltage transformer in series to collect its current signal in the resistance division circuit. The collected current signal is output through 1:1, and then the output signal of the voltage transformer is converted into a voltage signal through resistance, and then the voltage signal is integrated and adjusted, and finally the voltage signal is filtered and output to the A/D processor.

In order to realize the above-mentioned technical scheme, the circuit described in the utility model is composed of a power transformer T, a safety capacitor XC, a varistor RV, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a capacitor C1, Composed of capacitor C2, the power transformer T has 4 pins, pin 1 is connected to one end of resistor R1, the other end of resistor R1 is connected to safety capacitor XC and one end of varistor RV, and then connected to voltage signal W ;Pin 2 of the power transformer T is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the safety capacitor XC and the other end of the varistor RV, and then connected to the voltage signal N; the pin of the power transformer T 3 Connect to one end of resistor R3, resistor R4, and resistor R6, and connect the connected node to GND; pin 4 of power transformer T is connected to resistor R3, the other end of resistor R4, and one end of resistor R5; the other end of resistor R5, resistor R6 The other end of the capacitor C1 and one end of the capacitor C2 are connected respectively, and at the same time, they correspond to the mains voltage AC signal acquisition terminals that lead out the mains voltage AC signal V+ and the mains voltage AC signal V-; the other end of the capacitor C1 and the capacitor C2 are connected to GND.

Safety capacitors and varistors are used for double protection before the AC voltage signal is input, and then high-precision (low temperature drift error 1/1000) resistors are used to divide the AC voltage and then collect its current, ensuring data The accuracy is satisfied when the collected current passes through the voltage transformer, and the signal obtained after the collected current is converted into a voltage signal with a precision (low temperature drift error of 1/1,000) resistance, which once again ensures the accuracy of the signal to be collected. Accuracy, the voltage transformer used has an isolated high voltage of 3000V, so the signal processed by this circuit can communicate with the A/D processor safely and stably.

Description of drawings

Fig. 1 is the principle diagram of one way AC voltage acquisition circuit of the utility model.

Fig. 2 is a method for the application of the utility model in three-phase four-wire AC collection.

detailed description

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, each mains AC voltage acquisition circuit includes a power transformer T, a safety capacitor XC, a varistor RV, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, and a capacitor C1 , Capacitor C2. Connect the safety capacitor XC and the varistor RV in parallel. After parallel connection, one end is connected to the voltage signal W, and the other end is connected to the voltage signal N; one end of the resistor R1 is connected to the voltage signal W, and the other end is connected to the first pin of the voltage transformer T; the resistor R2 One end is connected to the voltage signal N, and the other end is connected to the second pin of the voltage transformer T; the resistor R3 and the resistor R4 are connected in parallel, and one end of the parallel connection is connected to the fourth pin of the voltage transformer T, and the other end is connected to the first pin of the voltage transformer 3 pins; one end of the resistor R5 is connected to the fourth pin of the voltage transformer T; one end of the resistor R6 is connected to the third pin of the voltage transformer T; one end of the capacitor C1 is connected to the other end of the resistor R5, and the other end of the capacitor C1 is grounded; One end of capacitor C2 is connected to the other end of resistor R6, and the other end of capacitor C2 is grounded; finally there is signal V+ between resistor R5 and capacitor C1, and signal V- between resistor R6 and capacitor C2; V+ and V- are the utility model The mains voltage AC signal to be collected.

Claims (1)

1. an AC voltage sampling circuit, it is characterized in that described circuit is made up of power transformer T, safety electric capacity XC, voltage dependent resistor (VDR) RV, resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, electric capacity C1, electric capacity C2, wherein power transformer T has 4 pins, pin 1 is connected with one end of resistance R1, and the other end of resistance R1 is connected with one end of safety electric capacity XC, voltage dependent resistor (VDR) RV and connects with voltage signal W afterwards; The pin 2 of power transformer T is connected with one end of resistance R2, and the other end of resistance R2 is connected with the other end of safety electric capacity XC, voltage dependent resistor (VDR) RV and connects with voltage signal N afterwards; The pin 3 of power transformer T is connected with one end of resistance R3, resistance R4, resistance R6, and connected node meets GND; The pin 4 of power transformer T is connected with one end of resistance R3, the resistance R4 other end and resistance R5; The other end of resistance R5, the other end of resistance R6 are connected with one end of electric capacity C1, electric capacity C2 respectively, and correspondence draws the line voltage ac signal acquisition end of line voltage AC signal V+ and line voltage AC signal V-respectively simultaneously; Another termination GND of electric capacity C1, electric capacity C2.