A kind of ammeter relay switching on control circuit and intelligent electric meter
Technical field
The present invention relates generally to a kind of switching on control circuit being applied to ammeter, and a kind of intelligent electric meter with this control circuit.
Background technology
Along with the development need of intelligent grid, the functions such as pre-payment, carrier communication, remote meter reading, Long-distance Control are applied on ammeter gradually.The switching on function of ammeter becomes the necessary circuits controlling power supply.Traditional switching on circuit is by transformer-supplied, and H bridge controls switching on, there is following problem: switching on voltage causes switching on baulk not when low-voltage inputs; H-bridge circuit is complicated, and the inverse electromotive force that protection Design is improper when being easily turned off punctures triode; Transformer frequency response internal resistance is little, and upper and lower bridge arm together conducting can burn triode and causes the problems such as switching on circuit malfunction.
Summary of the invention
The present invention is intended to the defect solving prior art existence, design a kind of switching on control circuit being applied to ammeter, electric current in switching on circuit effectively can be avoided excessive and cause the situation losing efficacy or damaged to occur, and a kind of ammeter with energy-saving and cost-reducing power source design is provided.
In order to realize above-mentioned purpose of design, the present invention is achieved through the following technical solutions:
Technical scheme 1: a kind of ammeter relay switching on control circuit, comprise capacitance-resistance voltage reduction circuit, power control circuit, comprise constant-current charging circuit further, equalizer circuit and switching circuit, the wherein input of electrical network zero line N and live wire L voltage signal access capacitance-resistance voltage reduction circuit, the output of described capacitance-resistance voltage reduction circuit is electrically connected to power control circuit, described power control circuit is electrically connected to constant-current charging circuit, described constant-current charging circuit is electrically connected to the equalizer circuit and switching circuit that intercouple further, described switching circuit carries out switching on action by its relay.
Further, in a preferred embodiment of the invention, described capacitance-resistance voltage reduction circuit is by resistance MOV1, R1, safety electric capacity C1, diode D1, D3, D4 and electrochemical capacitor E1 form, wherein between the zero line N and live wire L circuit of capacitance-resistance voltage reduction circuit, be equipped with resistance MOV1, described resistance MOV1 is piezo-resistance; Be equipped with diode D3 further, D4, described diode D3, D4 are voltage stabilizing didoe, for the power supply setting clamp voltage external to capacitance-resistance voltage reduction circuit; Be equipped with electrochemical capacitor E1 further.
Further, in a preferred embodiment of the invention, described power control circuit is by resistance R2, R3, R4, R5, triode Q1, Q5, diode D2 forms, and wherein resistance R2 is current sampling resistor, and it is connected to voltage stabilizing didoe D4, outside an external power supply to be powered to ammeter by capacitance-resistance voltage reduction circuit, residual current flows back into capacitance-resistance voltage reduction circuit by described resistance R2; Resistance R3 is by voltage stabilizing didoe D3, and be connected to triode Q5 between D4, triode Q1, Q5 establish resistance R4, R5 indirectly.
Further, in a preferred embodiment of the invention, described equalizer circuit is made up of voltage stabilizing didoe D5, D6, resistance R8, R9 and switching on electric capacity E2, E3, and wherein said switching on electric capacity E2, E3 are external to an external power supply; Described diode D5, D6 are connected to switching on electric capacity E2, E3 to make switching on electric capacity E2, the impartial and mA level current loss of the charging voltage of E3; Described resistance R8, R9 are connected to switching on electric capacity E2 further, E3 and be external to the ADC sample port of ammeter processor.
Further, in a preferred embodiment of the invention, described constant-current charging circuit is by resistance R7, R6 and triode Q2, Q3 forms, wherein between the resistance R7 emitter that is connected to triode Q2 and base stage, between the base stage that resistance R6 is connected to triode Q3 and collector electrode, described triode Q2, Q3 intercouple to form a crossing current circuit.
Further, in a preferred embodiment of the invention, described switching circuit is by resistance R10, R11, R12, R13, R14, R15, triode Q4, Q6, Q7 and relay composition, and wherein resistance R13, R14 form pull down resistor; Triode Q4, Q6 and resistance R10, R11, R12 are of coupled connections closed with control relay; Triode Q7 and resistance R15 is of coupled connections and disconnects with control relay.
Further, in a preferred embodiment of the invention, when the voltage at resistance R2 two ends reaches the conducting voltage of triode Q5, the voltage at resistance R2 two ends makes described triode Q5 conducting by resistance R3, from and make triode Q1 conducting by resistance R5, described triode Q1 powers to late-class circuit.When late-class circuit supply current increases, the electric current flowing through resistance R2 reduces finally to make triode Q5 be in magnifying state, and triode Q1 is pulled to magnifying state with the supply current of restriction to late-class circuit by resistance R4.When operating current needed for ammeter increases, resistance R2 makes the electric current of late-class circuit reduce after regulating.When meter circuit needs Transient Currents to power, be stored in described switching on electric capacity E2, the electric energy in E3 provides spark electric current by diode D2; Power control circuit preferentially ensures that the normality of ammeter functional circuit part is powered and Transient Currents power demands, and unnecessary electric energy is powered to the abnormal operating circuit of rear end again.As switching on electric capacity E2, during E3 underfill electricity, resistance R6 makes its conducting to triode Q3 is drop-down, electric current passes through resistance R7 and triode Q3 to rear end switching on electric capacity E2, E3 charges, the voltage drop that current flowing resistance R7 produces makes triode Q2 conducting, and triode Q2 conducting again limit the conducting of triode Q3, simultaneously limiting resistance R7 electric current thus form a crossing current circuit.As described switching on electric capacity E2, when E3 is full of electricity, described crossing current circuit no longer current sinking itself, improves power-efficient.It is constant that constant-current charging circuit compares crosstalk resistance current-limiting charge whole charging ring current, reduces impulse current when powering on, shorten the charging interval.
Technical scheme 2: a kind of intelligent electric meter, it comprises processor and display circuit, comprise power supply VCC further, and foregoing relay switching on control circuit, wherein capacitance-resistance voltage reduction circuit connects power supply VCC and is 24V by its diode D3, D4 by the magnitude of voltage clamper of power supply VCC; Described power supply VCC is connected to display circuit, processor and equalizer circuit further and provides operating voltage for it; Described processor is connected to equalizer circuit (4) by ADC sample port and judges its switching on electric capacity E2, and whether E3 charges complete to carry out switching on operation.
Further, in a preferred embodiment of the invention, processor can judge switching on electric capacity E2 by ADC sample port, and whether E3 charges and completely can carry out switching on operation, improves the reliability that each switching on operates.
Further, in a preferred embodiment of the invention, the pull down resistor of resistance R13, R14 composition ensures that processor can not carry out misoperation to relay before completing I/O initialization.When closing operation, the switching signal of processor makes Q4 conducting by R12, Q6, R11, and the electric energy stored in E2 to be powered to relay by Q4 and made relay adhesive; When operating a switch operation, the signal of operating a switch of processor makes Q7 conducting by R15, and the electric energy stored in E3 to be powered to relay by Q7 and relay is operated a switch.
The invention has the beneficial effects as follows apparent, switching on circuit of the present invention effectively can avoid the potential faults caused because of switching on electric voltage over press or deficiency, and circuit structure is simple, provides a kind of power source design effectively utilizing supply power voltage simultaneously.The technical scheme scope of application of the present invention is extremely extensive, and can reduce costs ammeter internal circuit design.
Accompanying drawing explanation
The preferred embodiment of the present invention will embodied in detail below by way of the mode with reference to accompanying drawing, and the identical function components/modules in figure is marked with same-sign, wherein
Fig. 1 is the circuit theory diagrams of the preferred embodiment of ammeter relay switching on control circuit of the present invention;
Fig. 2 is the structure principle chart of intelligent electric meter of the present invention.
Embodiment
With reference to Fig. 1, the preferred embodiment of ammeter relay switching on control circuit of the present invention comprises capacitance-resistance voltage reduction circuit 1, power control circuit 2, comprise constant-current charging circuit 3 further, equalizer circuit 4 and switching circuit 5, the wherein input of electrical network zero line N and live wire L voltage signal access capacitance-resistance voltage reduction circuit 1, the output of described capacitance-resistance voltage reduction circuit 1 is electrically connected to power control circuit 2, described power control circuit 2 is electrically connected to constant-current charging circuit 3, described constant-current charging circuit 3 is electrically connected to the equalizer circuit 4 and switching circuit 5 that intercouple further, described switching circuit 5 carries out switching on action by its relay K.
In a preferred embodiment of the invention, capacitance-resistance voltage reduction circuit 1 is by resistance MOV1, R1, safety electric capacity C1, diode D1, D3, D4 and electrochemical capacitor E1 forms, and wherein between the zero line N and live wire L circuit of capacitance-resistance voltage reduction circuit 1, be equipped with resistance MOV1, described resistance MOV1 is piezo-resistance; Be equipped with diode D3 further, D4, described diode D3, D4 are voltage stabilizing didoe, set clamp voltage for the power supply VCC external to capacitance-resistance voltage reduction circuit (1); Be equipped with electrochemical capacitor E1 further.VCC voltage is made to be 24V by the clamper of D3 and D4.VCC circuit is except the computation chip for ammeter, and MCU, the power supply such as liquid crystal drive is outer is also responsible for switching on capacitor charging.
In a preferred embodiment of the invention, power control circuit 2 is by resistance R2, R3, R4, R5, triode Q1, Q5, diode D2 forms, wherein resistance R2 is current sampling resistor, it is connected to voltage stabilizing didoe D4, and outside an external power supply VCC is powered by capacitance-resistance voltage reduction circuit 1 pair of ammeter, residual current flows back into capacitance-resistance voltage reduction circuit 1 by described resistance R2; Resistance R3 is by voltage stabilizing didoe D3, and be connected to triode Q5 between D4, triode Q1, Q5 establish resistance R4, R5 indirectly.
Wherein, R2 is current sampling resistor, and the constant-current source be made up of capacitance-resistance voltage reduction circuit 1 is except giving ammeter functional circuit for except electric current, and remaining electric current flows back to constant-current source circuit by R2.When the voltage at R2 two ends reaches the conducting voltage of Q5, the voltage at R2 two ends makes Q5 conducting by R3, Q5 conducting makes Q1 conducting by R5 again, Q1 powers to back-end circuit, when back-end circuit supply current increases, the electric current flowing through R2 reduces final Q5 and is in magnifying state, and Q1 is in magnifying state by R4 pull-up and limits supply current to back-end circuit.When the portion of electrical current increase in demand of ammeter functional circuit, reduce to the electric current of back-end circuit after being regulated by R2.When functional circuit needs Transient Currents to power, the electric energy be stored in switching on electric capacity can provide spark electric current by D2 again.Power control circuit preferentially ensures that the normality of ammeter functional circuit part is powered and Transient Currents power demands, and unnecessary electric energy is powered to the abnormal operating circuit of rear end again.
With reference to Fig. 2, in a preferred embodiment of the invention, equalizer circuit 4 is made up of voltage stabilizing didoe D5, D6, resistance R8, R9 and switching on electric capacity E2, E3, and wherein said switching on electric capacity E2, E3 are external to an external power supply VCC; Described diode D5, D6 are connected to switching on electric capacity E2, and E3 is to make its charging voltage impartial and for mA level current loss; Described resistance R8, R9 are connected to switching on electric capacity E2 further, E3 and be external to the ADC sample port of ammeter processor 10.D5, D6 ensure that 2 switching on capacitor charging voltages of connecting are equal, avoid again the mA level current loss of conventional capacitance divider resistance band simultaneously.The divider resistance of R8 and R9 composition connects the ADC thief hatch of processor, and by ADC sampling, processor can judge whether switching on electric capacity charges completely can carry out switching on operation, improves the reliability that each switching on operates.
See figures.1.and.2, in a preferred embodiment of the invention, constant-current charging circuit 3 is by resistance R7, R6 and triode Q2, Q3 forms, wherein between the resistance R7 emitter that is connected to triode Q2 and base stage, between the base stage that resistance R6 is connected to triode Q3 and collector electrode, described triode Q2, Q3 intercouple to form a crossing current circuit.As switching on electric capacity E2, during E3 underfill electricity, R6 causes Q3 conducting to Q3 is drop-down, and electric current passes through R7, Q3 to rear end switching on capacitor charging, the voltage drop that electric current flows through R7 generation makes Q2 conducting, Q2 conducting again limit the conducting of Q3, again limit the electric current of R7 conversely thus forms a crossing current circuit, when rear end switching on electric capacity is full of electricity, crossing current circuit no longer current sinking itself, improves power-efficient.It is constant that constant-current charging circuit compares crosstalk resistance current-limiting charge whole charging ring current, reduces impulse current when powering on, shorten the charging interval.
In a preferred embodiment of the invention, switching circuit 5 is by several resistance R10, R11, R12, R13, R14, R15, triode Q4, Q6, Q7 and relay K composition, and wherein resistance R13, R14 form pull down resistor; Triode Q4, Q6 and resistance R10, R11, R12 are of coupled connections closed with control relay K; Triode Q7 and resistance R15 is of coupled connections and disconnects with control relay K.The pull down resistor of R13, R14 composition ensures that processor can not carry out misoperation to relay before completing I/O initialization.During closing operation, the switching signal of processor makes Q4 conducting by R12, Q6, R11, and the electric energy stored in E2 to be powered to relay by Q4 and made relay adhesive.Operate a switch operation time, the signal of operating a switch of processor makes Q7 conducting by R15, and the electric energy stored in E3 to be powered to relay by Q7 and relay is operated a switch.
When the voltage at resistance R2 two ends reaches the conducting voltage of triode Q5, the voltage at resistance R2 two ends makes described triode Q5 conducting by resistance R3, from and make triode Q1 conducting by resistance R5, described triode Q1 powers to late-class circuit; When late-class circuit supply current increases, the electric current flowing through resistance R2 reduces until triode Q5 is in magnifying state, and triode Q1 is pulled to magnifying state with the supply current of restriction to late-class circuit by resistance R4; When operating current needed for ammeter increases, resistance R2 makes the electric current of late-class circuit reduce after regulating; When meter circuit needs Transient Currents to power, be stored in described switching on electric capacity E2, the electric energy in E3 provides spark electric current by diode D2; As switching on electric capacity E2, during E3 underfill electricity, resistance R6 makes its conducting to triode Q3 is drop-down, electric current passes through resistance R7 and triode Q3 to rear end switching on electric capacity E2, E3 charges, the voltage drop that current flowing resistance R7 produces makes triode Q2 conducting, and triode Q2 conducting again limit the conducting of triode Q3, simultaneously limiting resistance R7 electric current thus form a crossing current circuit.
Fig. 2 shows a kind of intelligent electric meter, it comprises processor 10 and display circuit 20, it is characterized in that: comprise power supply VCC further, and relay switching on control circuit 30 as claimed in claim 1, wherein capacitance-resistance voltage reduction circuit 1 connects power supply VCC and is 24V by its diode D3, D4 by the magnitude of voltage clamper of power supply VCC; Described power supply VCC is connected to display circuit 20, processor 10 and equalizer circuit 4 further and provides operating voltage for it; Described processor 10 is connected to equalizer circuit 4 by ADC sample port and judges its switching on electric capacity E2, and whether E3 charges complete to carry out switching on operation.These are only the preferred embodiment of the present invention, being intended to embody outstanding technique effect of the present invention and advantage, is not the restriction to technical scheme of the present invention.Those skilled in the art will appreciate that all are based on the amendment done by the technology of the present invention content, change or substitute technology feature, all should be covered by the technology category of claims of the present invention opinion.