CN205080188U - Thyristor zero cross detection circuit - Google Patents

Abstract

The utility model discloses a thyristor zero cross detection circuit, including bleeder circuit, voltage clamp circuit, voltage follower circuit, filter circuit, bleeder circuit comprises resistance R1, resistance R2 and resistance R7, the voltage clamp circuit comprises positive supply clamper R. +V, negative supply clamper R. -V, diode D1, diode D2 and diode D3, second order filter circuit comprises resistance R5, resistance R6, filter capacitance C2, filter capacitance C3, voltage follower circuit by integrated fortune put U1 2, the output short circuit constitutes. Compared with the prior art, the utility model the advantage be: the utility model discloses a detection circuitry is simple reliable, stable, and can realize that a circuit detects out voltage zero cross signal and symbol signal simultaneously.

Description

A kind of thyristor zero cross detection circuit

Technical field

The utility model relates to testing circuit, particularly relates to a kind of thyristor zero cross detection circuit.

Background technology

Along with the development of Power Electronic Technique and Computer Control Technology, various novel automatic, Quick reactive-load compensation device occur in succession, and thyristor switchable capacitor (TSC) is exactly a kind of dynamic reactive compensation device being widely used in distribution system.Compared with mechanical switched capacitor, the open and close of thyristor are contactless, and its operation lifetime is almost unlimited, and the switching moment of thyristor can accurately control, capacitor can be accessed electrical network, dash current when greatly reducing switching and operating difficulties without impacting ground fast.In Quick reactive-load compensation and harmonic filtering installation, with thyristor as executive component switched capacitor.TSC requires to trigger at thyristor voltage zero crossing, and determine that the method for thyristor voltage zero crossing has two kinds, one obtains synchronizing signal from line voltage, and a kind of is got zero-signal from the anode of thyristor and negative electrode.But the testing circuit of conventional voltage zero cross signal is complicated and unstable; A circuit cannot be realized and detect voltage zero-crossing signal and mark signal simultaneously.

Utility model content

The utility model is to solve above-mentioned deficiency, provides a kind of thyristor zero cross detection circuit.

Above-mentioned purpose of the present utility model is realized by following technical scheme: a kind of thyristor zero cross detection circuit, is characterized in that: comprise bleeder circuit, voltage clamp circuit, voltage follower circuit, filtering circuit;

Described bleeder circuit is made up of resistance R1, resistance R2 and resistance R7;

Described voltage clamp circuit is made up of positive supply clamper R.+V, negative supply clamper R.-V, diode D1, diode D2 and diode D3;

Described second-order filter circuit is made up of resistance R5, resistance R6, filter capacitor C2, filter capacitor C3;

Described voltage follower circuit is made up of the negative input end of integrated transporting discharging U1, positive input terminal short circuit;

Described bleeder circuit and voltage clamp circuit are all connected to the integrated transporting discharging U1 positive input terminal of voltage follower circuit, and the integrated transporting discharging U1 output terminal of described voltage follower circuit connects filtering circuit.

The utility model advantage is compared with prior art: testing circuit of the present utility model is simple and reliable, stable, and can realize a circuit and detect voltage zero-crossing signal and mark signal simultaneously.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of thyristor switchable capacitor.

Fig. 2 is thyristor zero cross detection circuit figure of the present utility model.

Embodiment

Below in conjunction with accompanying drawing, the utility model is described in further detail.

As shown in Figure 2, a kind of thyristor zero cross detection circuit, comprises bleeder circuit, voltage clamp circuit, voltage follower circuit, filtering circuit; Described bleeder circuit is made up of resistance R1, resistance R2 and resistance R7; Described voltage clamp circuit is made up of positive supply clamper R.+V, negative supply clamper R.-V, diode D1, diode D2 and diode D3; Described second-order filter circuit is made up of resistance R5, resistance R6, filter capacitor C2, filter capacitor C3; Described voltage follower circuit is made up of the negative input end of integrated transporting discharging U1, positive input terminal short circuit;

Described bleeder circuit and voltage clamp circuit are all connected to the integrated transporting discharging U1 positive input terminal of voltage follower circuit, and the integrated transporting discharging U1 output terminal of described voltage follower circuit connects filtering circuit.

As shown in Figure 1, the principle of thyristor switchable capacitor, when line voltage sampled signal, mains current signal is delivered in controller, when controller judges to need switching capacitance, controller can when thyristor VT both end voltage be zero, drive to VT and send trigger pip, make VT conducting, electric capacity is put in electrical network, with the dash current that the reactance of capacitances in series is to suppress electric capacity to drop into electrical network moment, can also amplify by harmonic inhabitation when selecting suitable reactance.

As shown in Figure 2, the utility model thyristor one terminal voltage R.CAP(is near electric capacity) and thyristor one terminal voltage R.PHASE(near mains supply) connect thyristor both end voltage, C1 is filter capacitor; Integrated transporting discharging output terminal current potential is resistance R2/R1+R2+R7 dividing potential drop thyristor both end voltage.When thyristor both end voltage is higher, positive supply clamper R.+V and negative supply clamper R.-V, by diode D1, D2, D3 clamper integrated transporting discharging output end voltage, prevents thyristor both end voltage excessive and burns out integrated transporting discharging; When thyristor both end voltage is lower be less than 1V time, diode D2, D3 not conducting, integrated transporting discharging output end voltage is R.CAP and R.PHASE both end voltage, now integrated transporting discharging U1 is a voltage follower, obtains R.CAP and R.PHASE and thyristor two ends zero passage voltage signal and mark signal.

The foregoing is only embodiment of the present utility model; not thereby the scope of the claims of the present utility model is limited; every utilize the utility model instructions and accompanying drawing content to do equivalent structure or equivalent flow process conversion; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present utility model.

Claims (1)

1. a thyristor zero cross detection circuit, is characterized in that: comprise bleeder circuit, voltage clamp circuit, voltage follower circuit, filtering circuit;

Described bleeder circuit is made up of resistance R1, resistance R2 and resistance R7;

Described voltage clamp circuit is made up of positive supply clamper R.+V, negative supply clamper R.-V, diode D1, diode D2 and diode D3;

Described second-order filter circuit is made up of resistance R5, resistance R6, filter capacitor C2, filter capacitor C3;

Described voltage follower circuit is made up of the negative input end of integrated transporting discharging U1, positive input terminal short circuit;

Described bleeder circuit and voltage clamp circuit are all connected to the integrated transporting discharging U1 positive input terminal of voltage follower circuit, and the integrated transporting discharging U1 output terminal of described voltage follower circuit connects filtering circuit.