CN201233423Y - Electric network voltage detection device - Google Patents

Abstract

The utility model relates to an electric network voltage detection device, which comprises a rectifying circuit, a zero-point detection circuit, a voltage division circuit, a single steady-state pulse trigger circuit and a calculation unit, wherein, the rectifying circuit converts the alternative-current electric network voltage to be the direct-current voltage waveform; the zero-point detection circuit detects the zero point of the alternative-current electric network voltage and outputs the zero-point pulse; the voltage division circuit narrows the direct-current voltage waveform to be a low-voltage waveform of a logic circuit according to the ratio; the single steady-state pulse trigger circuit receives the low-voltage waveform and generates a single steady-state pulse when the voltage on the low-voltage waveform reaches a reference electric level; a time difference is arranged between the single steady-state pulse and the zero-point pulse; the calculation unit calculates the voltage value of the alternative-current electric network according to the time difference between the single steady-state pulse and the zero-point pulse as well as the alternative-current instant voltage at the moment when the single steady-state pulse is generated. The device is free from a transformer, and has low power consumption and low cost, and can instantly monitor the voltage and the frequency of the electric network.

Description

The network voltage detection device

Technical field

The utility model relates to a kind of network voltage detection device, particularly a kind of real-time detection apparatus of measuring line voltage without transformer.

Background technology

The line voltage of countries in the world has a lot all different, and therefore a lot of electronic products need carry out different countermeasures at various line voltages and enable operate as normal.Wherein primary problem is a detection of grid voltage.

Present network voltage detection generally is to adopt transformer, makes high alternating voltage conversion and is isolated into low voltage, and then measure with A/D collection and single-chip microcomputer.As shown in Figure 1, the primary side of ac grid voltage 101 input transformers 102, because elementary umber of turn is many, the secondary winding turn ratio is less, like this low-voltage can be isolated and produce, after diode 103 rectifications and electric capacity 104 filtering, a smoother DC voltage can be become, through being defeated by A/D sample circuit 107 after resistance 105 and 106 dividing potential drops, be defeated by single-chip microcomputer 108 at last and detect then.

The problem that above-mentioned network voltage detection circuit exists is, the price of transformer is relatively costly, and volume is also bigger.Simultaneously, such method can not be measured the frequency of line voltage, has certain limitation.In addition, use transformer to detect voltage in real time, the power consumption that consumes on transformer is also bigger.

The utility model content

The utility model promptly proposes in view of above-mentioned defective, and purpose is to provide a kind of network voltage detection device, can realize voltage isolation, can save the transformer of large volume again, thereby realizes network voltage detection cheaply.

For this reason, the utility model proposes a kind of network voltage detection device, comprise rectification circuit, zero-detection circuit, bleeder circuit, monostable pulsed triggering circuit and arithmetic element.Rectification circuit is converted to DC voltage waveform with ac grid voltage; Zero-detection circuit connects this rectification circuit, detects the zero point of this ac grid voltage and exports the pulse at zero point in view of the above; Bleeder circuit connects this rectification circuit, with the scaled low-voltage waveform to logical circuit of this DC voltage waveform; The monostable pulsed triggering circuit connects this bleeder circuit, receives this low-voltage waveform, and the moment that voltage reaches a datum on this low-voltage waveform produce the monostable pulse, wherein have the mistiming between this monostable pulse and this pulse at zero point; Arithmetic element connects this zero-detection circuit and this monostable pulsed triggering circuit, calculates the magnitude of voltage of this ac grid voltage according to the AC network instantaneous voltage in the mistiming between this monostable pulse and the pulse at zero point and this monostable pulse generation moment.

In above-mentioned network voltage detection device, also can comprise: first photoelectric isolating circuit is connected between this zero-detection circuit and this arithmetic element; And second photoelectric isolating circuit, be connected between this monostable pulsed triggering circuit and this arithmetic element.

In above-mentioned network voltage detection device, comprise this AC network instantaneous voltage value of determining according to the intrinsic standoff ratio of this datum and this bleeder circuit in this arithmetic element.

In above-mentioned network voltage detection device, this rectification circuit is a full-wave rectifying circuit.

In above-mentioned network voltage detection device, this arithmetic element comprises single-chip microcomputer.

Network voltage detection device of the present utility model does not adopt transformer, and low in energy consumption, price is low, and can monitor the voltage and the frequency of electrical network in real time.

Description of drawings

For above-mentioned purpose of the present utility model, feature and advantage can be become apparent, below in conjunction with accompanying drawing embodiment of the present utility model is elaborated, wherein:

Fig. 1 is present conventional electrical network testing circuit synoptic diagram.

Fig. 2 is the block scheme of electrical network pick-up unit of the present utility model.

Fig. 3 a-Fig. 3 c is the each several part voltage oscillogram of electrical network pick-up unit of the present utility model, and wherein Fig. 3 a is the oscillogram of input AC line voltage; Fig. 3 b is the DC voltage waveform figure behind overcommutation; Fig. 3 c is the later low-voltage waveform figure of process dividing potential drop.

Fig. 4 is the pulse at zero point and the monostable timing chart of electrical network pick-up unit of the present utility model.

Fig. 5 is the circuit theory diagrams of an embodiment of electrical network pick-up unit of the present utility model.

Embodiment

As shown in Figure 2, electrical network pick-up unit of the present utility model embodiment comprises rectification circuit 202, bleeder circuit 203, monostable pulsed triggering circuit 204, zero-detection circuit 205 and arithmetic element 206.In a preferred embodiment, the electrical network pick-up unit also can comprise first photoelectric isolating circuit 207 and second photoelectric isolating circuit 208.

The voltage Vin of rectification circuit 202 input AC electrical networks 201, its voltage waveform are shown in Fig. 3 a, and wherein ac grid voltage can be 110V line voltage (shown in a solid line), also can be 220V line voltages (shown in dotted line).Rectification circuit 202 is full-wave rectifying circuits, and an one embodiment is a bridge rectifier as shown in Figure 5.Be converted into DC voltage waveform through rectification circuit 202 back ac grid voltages, its voltage waveform is divided into two-way to voltage then and gives zero-detection circuit 205 and monostable pulsed triggering circuit 204 respectively shown in Fig. 3 b.

Zero-detection circuit 205 is a circuit known in the art, therefore is not described in detail at this.Zero-detection circuit 205 can not only provide the pulse signal Pz at zero point (as shown in Figure 4) of a voltage over zero, the supply voltage (with reference to the VTEMP among Fig. 5) of a logical circuit can also be provided, be used for to monostable pulsed triggering circuit 204 and photoelectric isolating circuit 207,208 power supplies.

Bleeder circuit 203 is connected to rectification circuit 202, with the scaled low-voltage waveform to logical circuit of DC voltage waveform (shown in Fig. 3 c).An example of bleeder circuit 203 as shown in Figure 5; wherein diode D1 is used for making the A point voltage between R1, the R2 to be no more than 6V; make B point voltage between R2, the R3 be unlikely to surpass the maximum permissible voltage of follow-up chip (as 74HC123) input pin, shield.Fig. 3 c is depicted as the low-voltage waveform that B is ordered after the dividing potential drop, this low-voltage waveform input monostable pulsed triggering circuit 204.

Monostable pulsed triggering circuit 204 is connected to bleeder circuit 203, and monostable pulsed triggering circuit 204 receives the low-voltage waveform of Fig. 3 c, and the moment that voltage reaches a datum on this low-voltage waveform produce monostable pulse Ps, as shown in Figure 4.This datum can be logic high, and datum is relevant with the AC network instantaneous voltage that monostable pulse Ps produces the moment.

An example of monostable pulsed triggering circuit 204 as shown in Figure 5, the monostable pulse trigger is selected 74HC123 for use in this circuit, its input end is Schmidt (Schmitt) input, can improve antijamming capability.If input voltage value is greater than the datum of 3.5V, then high level is thought in input, can produce a monostable pulse this moment, this pulse width is by R4 and C3 decision, requirement can guarantee that the single-chip microcomputer of light current end reliably detects timely, is not again very long simultaneously, makes the light emitting diode among the photocoupler U3 can not consume too many power consumption, VTEMP can stablize, and the power consumption of entire circuit can be very little.Light emitting diode among the U3 in this monostable pulsed drive first photoelectric isolating circuit 208 then, in the light current pressure side pulse Ps signal appears also through photoelectricity coupling back, be the pulse signal of voltage detecting, be defeated by single-chip microcomputer at last as arithmetic element 206.

Get back to shown in Figure 2ly, arithmetic element 206 connects zero-detection circuit 205 and this monostable pulsed triggering circuits 204, and arithmetic element 206 can be gathered pulse at zero point Pz and monostable pulse Ps shown in Figure 4, between these two pulses a mistiming ts is arranged.Can calculate the frequency f of input AC line voltage by the mistiming between two pulse at zero point Pz.And reach datum and when producing monostable pulse Ps, usually can calculate the instantaneous voltage Vs of line voltage this moment by the intrinsic standoff ratio of datum size and bleeder circuit 203 when the monostable incoming level of deciding pulsed triggering circuit.If with physical circuit shown in Figure 5 is example, when the B point voltage is high level voltage (as 3.5V) (when producing a pulse), can calculate the instantaneous voltage Vs of line voltage this moment by physical circuit.An example of arithmetic element 206 is single-chip microcomputers as shown in Figure 5, can comprise the AC network instantaneous voltage value Vs that determines (perhaps further considering the physical circuit influence) in advance according to the intrinsic standoff ratio of above-mentioned datum and bleeder circuit in the arithmetic element 206.

Because the voltage of general electrical network all is sinusoidal wave, V=Vp*sin (2 π * f*t), when t=ts, V=Vs, then voltage peak Vp=Vs/sin (2* π * f*ts) can calculate then $\mathrm{Vrms}=\mathrm{Vp}/\sqrt{2},$ Be the effective value of AC network input voltage.Arithmetic element 206 produces AC network instantaneous voltage Vs constantly according to the mistiming ts between monostable pulse Ps and pulse at the zero point Pz and this monostable pulse thus, can calculate the magnitude of voltage of this ac grid voltage.

Comprehensive the above, the utility model is that electrical network is carried out dividing potential drop, and produces a pulse at a certain certain electric pressure point, calculates line voltage according to the time interval of this pulse and pulse at zero point then.The utility model has also additionally obtained mains frequency.Owing to do not adopt transformer in the circuit of the present utility model, thus low in energy consumption, price is low, volume is little.

Though the utility model discloses as above with preferred embodiment; right its is not in order to limit the utility model; any those skilled in the art; in not breaking away from spirit and scope of the present utility model; when doing a little modification and perfect, therefore protection domain of the present utility model is worked as with being as the criterion that claims were defined.

Claims (5)

1. network voltage detection device is characterized in that comprising:

Rectification circuit is converted to DC voltage waveform with ac grid voltage;

Zero-detection circuit connects this rectification circuit, detects the zero point of this ac grid voltage and exports the pulse at zero point in view of the above;

Bleeder circuit connects this rectification circuit, with the scaled low-voltage waveform to logical circuit of this DC voltage waveform;

The monostable pulsed triggering circuit connects this bleeder circuit, receives this low-voltage waveform, and the moment that voltage reaches a datum on this low-voltage waveform produce the monostable pulse, wherein have the mistiming between this monostable pulse and this pulse at zero point; And

Arithmetic element, connect this zero-detection circuit and this monostable pulsed triggering circuit, calculate the magnitude of voltage of this ac grid voltage according to the AC network instantaneous voltage in the mistiming between this monostable pulse and the pulse at zero point and this monostable pulse generation moment.

2. network voltage detection device as claimed in claim 1 is characterized in that, also comprises:

First photoelectric isolating circuit is connected between this zero-detection circuit and this arithmetic element; And

Second photoelectric isolating circuit is connected between this monostable pulsed triggering circuit and this arithmetic element.

3. network voltage detection device as claimed in claim 1 is characterized in that, comprises this AC network instantaneous voltage value of determining according to the intrinsic standoff ratio of this datum and this bleeder circuit in this arithmetic element.

4. network voltage detection device as claimed in claim 1 is characterized in that, this rectification circuit is a full-wave rectifying circuit.

5. network voltage detection device as claimed in claim 1 is characterized in that this arithmetic element comprises single-chip microcomputer.

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