CN202693675U - Power circuit for intelligent electric meter and three-phase intelligent electric meter with power circuit - Google Patents
Power circuit for intelligent electric meter and three-phase intelligent electric meter with power circuit Download PDFInfo
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- CN202693675U CN202693675U CN 201220314060 CN201220314060U CN202693675U CN 202693675 U CN202693675 U CN 202693675U CN 201220314060 CN201220314060 CN 201220314060 CN 201220314060 U CN201220314060 U CN 201220314060U CN 202693675 U CN202693675 U CN 202693675U
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Abstract
The utility model discloses a power circuit for an intelligent electric meter. The power circuit comprises a power output control circuit, a step-down circuit, an on-off control circuit and a charging circuit, wherein the input end and the output end of the step-down circuit are respectively connected to the wiring end of the electric meter and the input end of the on-off control circuit; and the output end of the on-off control circuit is connected to the power output control circuit. The utility model also discloses a three-phase intelligent electric meter with the power circuit. According to the three-phase intelligent electric meter, the required current of the electric meter can be guaranteed when an operating circuit always normally works through the power circuit, and the current per milliampere provided by the power circuit is utilized to the greatest degree.
Description
Technical field
The utility model is about the technology of instrument and meter field, more particular words it, the utility model is the novel power configuration about a kind of intelligent electric meter, and further about having the three-phase intelligent ammeter of this type of power configuration.
Background technology
At present, ammeter manufacturing enterprise is in the actual design and application of ammeter, the general mode (hereinafter to be referred as the transformer frequency response scheme) of transformer+rectifier bridge+voltage stabilizing chip that adopts is powered to ammeter, and this kind power source design also is that present electric energy meter manufacturing enterprise is studied and the most ripe improved power source design repeatedly.But the transformer frequency response scheme exists the shortcomings such as volume is large, the consumption copper material is many, weight large, the electric voltage frequency specification is many, transformer is not general.
Simultaneously, when ammeter designs, in order to satisfy the normal range of operation requirement of 70% ~ 115%Un, the peak power that the power demand PIN of the whole table of electric energy meter should can provide during for 70%Un at input voltage less than the power unit circuit, therefore just cause the input voltage of electric energy meter when 70%Un is above, the residual current that power supply provides need to use voltage stabilizing diode to shunt, otherwise this part electric current just slatterns fully, does not obtain any effective utilization.
The utility model content
The utility model is intended to solve the defective that exists in the prior art, a kind of novel power source design is proposed, and a kind of reduction voltage circuit is proposed, utilize simultaneously a kind of voltage dropping power supply scheme with power stage control to come the characteristic of inheriting tradition power source design, namely utilize the power supply of constant current source character, and have power stage control, therefore can guarantee ammeter required electric current while when operating circuit work always, the every milliampere of electric current that utilizes substantially power circuit to provide.
The utility model is realized a kind of three-phase intelligent ammeter on the power source design basis of advocating again, and this ammeter has been save supplying cell when effectively utilizing power supply, simplified the wiring of ammeter internal circuit, with volume and the cost that further dwindles whole table.
Technique effect of the present utility model is achieved through the following technical solutions:
A kind of power circuit of intelligent electric meter, it is characterized in that: comprise power output control circuit, reduction voltage circuit, ON-OFF control circuit and charging circuit, the input end of described reduction voltage circuit and output terminal are connected to the terminals of ammeter and the input end of ON-OFF control circuit, the output terminal access power output control circuit of described ON-OFF control circuit.
Further, described reduction voltage circuit comprises from input end to output terminal RC circuit parallel with one another, from input end respectively with these circuit and the voltage dependent resistor (VDR) that connects and twin zener dioder, and be connected in mu balanced circuit between RC circuit and the output terminal; Perhaps
Described reduction voltage circuit comprises RC circuit, convection current diode and the electric capacity that is electrically connected successively from input end to output terminal, the TVS pipe, resistance, triode and the convection current diode that are electrically connected successively from input end to output terminal.
Further, described ON-OFF control circuit comprises a control chip, and it is electrically connected to the output terminal of reduction voltage circuit, and comprises a charging circuit, the output terminal access power output control circuit of described charging circuit; Perhaps
Described ON-OFF control circuit comprises a control chip and a spacing output circuit that is electrically connected with it, and further comprises a charging circuit, the output terminal access power output control circuit of described charging circuit.
Further, described power output control circuit comprises impulse output circuit connected with each other, suppresses circuit and bleeder circuit.
Further, the power that described ammeter power circuit produces satisfies relational expression PMAX=UTVSIMAX, wherein UTVS is step-down through suppressing the output voltage after the circuit clamper, and PMAX is the externally peak power output during the lower maximum output current IMAX of alternating voltage input of step-down.
Further, IMAX=I1+I2+I3+I4+ID, wherein I1 is the working current of ammeter, and I2 is the charging current that is dispensed to switching on/electric capacity, and I3 is the charging current that is dispensed to charging circuit, and I4 is discharge current, and ID is the by-pass current of ammeter power circuit.
Further, after switching on/electric capacity was full of electricity, I2 was zero, and after the charging circuit charging finished, I3 was zero.
Simultaneously, the utility model proposes a kind of three-phase intelligent ammeter, it comprises an ammeter body, be provided with several terminals in described ammeter body interior, processor, display circuit, communicating circuit and storer, and bring in by described wiring and to be arranged between mains supply line and the electrical network user load, it is characterized in that: further be provided with ammeter power circuit as claimed in claim 1,3 Acquisition Circuit and 3 computation chips, wherein said terminals are connected to respectively Acquisition Circuit and ammeter power circuit, described Acquisition Circuit is electrically connected to computation chip, described processor respectively with computation chip, power circuit, display circuit, communication terminal and storer are electrically connected.
Further, described terminals are arranged with the symmetrical expression mode of connection.
Further, described Acquisition Circuit comprises copper-manganese divided circuit and isolation sensor, and described terminals are connected to the input end of copper-manganese divided circuit, the output terminal access isolation sensor of described copper-manganese divided circuit.
Further, described ammeter body comprises cooperatively interact fenced upper shell and lower house, and described upper shell has been connected the terminals that are used for connecting electric network power line and electrical network user load with lower house.
Further, described upper shell and lower house are respectively equipped with the zigzag auxiliary section that mutually coincide.
Further, the fleam of described zigzag auxiliary section is 113 °.
Further, the sawtooth lateral length of described zigzag auxiliary section is 4.5mm, and vertically width is 1.5mm.
The utility model can guarantee ammeter required electric current while when operating circuit work always, the every milliampere of electric current that utilizes substantially power circuit to provide.
Description of drawings
The beneficial effects of the utility model will be by the in addition detailed description of mode with reference to accompanying drawing, and the same or similar mark among the figure represents the identical function components and parts, wherein
Fig. 1 is the circuit diagram as the first preferred embodiment of the utility model power circuit;
Fig. 2 is the circuit diagram as the second preferred embodiment of the utility model power circuit;
Fig. 3 is the circuit diagram of the power output control circuit of the utility model power circuit;
Fig. 4 is the circuit structure schematic diagram of the utility model three-phase intelligent ammeter;
Fig. 5 is the terminal structure schematic diagram of the utility model three-phase intelligent ammeter;
Fig. 6 is the external structure principle schematic of the utility model three-phase intelligent ammeter;
Fig. 7 is as the annexation synoptic diagram between the upper watchcase of the utility model preferred embodiment and lower watchcase;
Fig. 8 is the left half side part enlarged drawing of Fig. 3;
Fig. 9 is the right half side part enlarged drawing of Fig. 3.
Embodiment
With reference to Fig. 1, in the first embodiment of the power circuit of the utility model intelligent electric meter, power circuit 100 comprises power output control circuit, reduction voltage circuit 110 and ON-OFF control circuit 120, input end UA, the UB of described reduction voltage circuit, UC, UN and output terminal VIN are connected to the terminals of ammeter and the input end of ON-OFF control circuit, the output terminal access power output control circuit of described ON-OFF control circuit.
Further, described reduction voltage circuit 110 comprises from input end UA, UB, UC to output terminal DCVIN RC circuit 111 parallel with one another, from input end UN respectively with these RC circuit and the voltage dependent resistor (VDR) MOV1 that connects, MOV2, MOV3 and twin zener dioder D13, D17, D18, and be connected in mu balanced circuit 112 between RC circuit and the output terminal VIN.
Further, described ON-OFF control circuit 120 comprises a control chip 121, is preferably a MP2451 chip, and it is electrically connected to the output terminal DCVIN of reduction voltage circuit 110, and comprise a charging circuit 122, the output terminal V3P3S access power output control circuit of described charging circuit 122.
With reference to Fig. 2, in the second embodiment of the power circuit of the utility model intelligent electric meter, take a kind of single-phase intelligent ammeter as example, power circuit 100 comprises power output control circuit, reduction voltage circuit 110 ' and ON-OFF control circuit 120 ', input end UA, the UB of described reduction voltage circuit, UC, UN and output terminal VIN are connected to the terminals of ammeter and the input end of ON-OFF control circuit, the output terminal access power output control circuit of described ON-OFF control circuit.
Further, described reduction voltage circuit comprises RC circuit 111 ', convection current diode D4 and the electric capacity E1 that is electrically connected successively to output terminal DCVIN from input end UA, the TVS pipe D6, resistance R 8, triode Q1 and the convection current diode D5 that are electrically connected successively to output terminal DCVIN from input end UN.
Further, described ON-OFF control circuit comprises a control chip 121 ' (being preferably the MP2451 chip) and a spacing output circuit 123 ' that is electrically connected with it, and further comprise a charging circuit 122 ', the output terminal V3P3S access power output control circuit of described charging circuit 122 '.
With further reference to Fig. 1 and Fig. 2, in the 3rd embodiment of the power circuit of the utility model intelligent electric meter, power circuit 100 comprises power output control circuit, reduction voltage circuit 110 and ON-OFF control circuit 120, input end UA, the UB of described reduction voltage circuit, UC, UN and output terminal VIN are connected to the terminals of ammeter and the input end of ON-OFF control circuit, the output terminal access power output control circuit of described ON-OFF control circuit.
Further, described reduction voltage circuit 110 comprises from input end UA, UB, UC to output terminal DCVIN RC circuit 111 parallel with one another, from input end UN respectively with these RC circuit and the voltage dependent resistor (VDR) MOV1 that connects, MOV2, MOV3 and twin zener dioder D13, D17, D18, and be connected in mu balanced circuit 112 between RC circuit and the output terminal VIN.
Further, described ON-OFF control circuit comprises a control chip 121 ' (being preferably the MP2451 chip) and a spacing output circuit 123 ' that is electrically connected with it, and further comprise a charging circuit 122 ', the output terminal V3P3S access power output control circuit of described charging circuit 122 '.
In the 4th embodiment of the power circuit of the utility model intelligent electric meter, in the first embodiment of the power circuit of the utility model intelligent electric meter, power circuit 100 comprises power output control circuit, reduction voltage circuit 110 and ON-OFF control circuit 120, input end UA, the UB of described reduction voltage circuit, UC, UN and output terminal VIN are connected to the terminals of ammeter and the input end of ON-OFF control circuit, the output terminal access power output control circuit of described ON-OFF control circuit.
Further, described reduction voltage circuit comprises RC circuit 111 ', convection current diode D4 and the electric capacity E1 that is electrically connected successively to output terminal DCVIN from input end UA, the TVS pipe D6, resistance R 8, triode Q1 and the convection current diode D5 that are electrically connected successively to output terminal DCVIN from input end UN.Further, described ON-OFF control circuit 120 comprises a control chip 121, is preferably a MP2451 chip, and it is electrically connected to the output terminal DCVIN of reduction voltage circuit 110, and comprise a charging circuit 122, the output terminal V3P3S access power output control circuit of described charging circuit 122.
With reference to Fig. 3, the power output control circuit of the utility model power circuit comprises impulse output circuit 810, suppresses circuit I 820, suppresses circuit I I 830 and bleeder circuit 840, and described impulse output circuit 810 is electrically connected with inhibition circuit I 820, inhibition circuit I I 830 and bleeder circuit 840 respectively.
Such as Fig. 3, Fig. 8 and shown in Figure 9, impulse output circuit 810 is connected to the output terminal V3P3S of charging circuit 122 ' by its input end U5V, and by the processor that a function control end ISENSE accesses an ammeter, is preferably a single chip circuit.Single-chip microcomputer can be controlled current direction and the size of current of circuit.In Fig. 3, impulse output circuit is connected to bleeder circuit 840 by triode Q2 and an output terminal UTVS, and is tapped into inhibition circuit I 820, suppresses circuit I I 830 by triode Q5 and another output terminal UOUT2.Function control inputs voltage preferably inputs to triode Q2 by two amplifier U1A and U1B.
Further, suppress circuit I 820 and comprise interconnective two triode Q3 and Q4, suppress circuit I 820 and be mainly used in relay switching on/electric capacity to ammeter and whether carry out charging and discharging and judge and control.
Further, suppress circuit I I 830 and be provided preferably with single-chip microcomputer U2, and utilize a diode D10, capacitor C 7 and a current limiting capacitance E3 mainly as buffer circuit, namely two are suppressed that right and wrong are worked simultaneously between the circuit 820 and 830.
Further, bleeder circuit 840 preferably includes four amplifier U1D, U1E, U1F and U1C and two triode Q6 and Q7, and carries out earial drainage by its output terminal MVDD.
Further, the power that produces of described ammeter power circuit satisfies relational expression P
MAX=U
TVSI
MAX, U wherein
TVSFor the step-down process suppresses circuit I 820, suppresses the output voltage after circuit I I 830 clampers suppress, P
MAXBe the reduction voltage circuit lower maximum output current I of alternating voltage input externally
MAXThe time peak power output.
Further, I
MAX=I
1+ I
2+ I
3+ I
4+ I
D, I wherein
1Be the working current of ammeter, I
2Be the charging current of the switching on/electric capacity that is dispensed to the ammeter relay, I
3For being dispensed to the charging current of charging circuit 122, I
4Be the discharge current of bleeder circuit 840 generations, and I
DBy-pass current (not showing among the figure) for the ammeter power circuit.
Further, foregoing, suppressing circuit I and II is asynchronous working, namely after switching on/electric capacity is full of electricity, and I
2Be zero, after the charging circuit charging finishes, I
3Be zero.
With reference to Fig. 4, the utility model further proposes a kind of three-phase intelligent ammeter on the basis of ammeter power circuit, it comprises an ammeter body, be provided with several terminals in described ammeter body interior, processor 400, display circuit 500, communicating circuit 600 and storer 700, and bring in by described wiring and to be arranged between mains supply line and the electrical network user load, and further be provided with such as the described ammeter power circuit 100 of aforementioned techniques scheme, 3 Acquisition Circuit 201,202 and 203 and 3 computation chips 301,302 and 303, wherein said terminals are connected to respectively three Acquisition Circuit 201,202,203 input end IAP, IAN, IBP, IBN, ICP, ICN and ammeter power circuit, described each phase acquisition circuit 201,202 and 203 are electrically connected to computation chip 301,302 and 303, processor 400 respectively with computation chip 301,302 and 303, ammeter power circuit 100, display circuit 500, communicating circuit 600 and storer 700 are electrically connected.
Further, communicating circuit 600 can be preferably 485 communicating circuits, it can with an exterior light communication or wireless telecommunications system, for example PDA equipment carries out data transmission and exchange.
Further, with reference to Fig. 5, described terminals are arranged with the symmetrical expression mode of connection.Namely, it is that mode with central shaft ammeter body central axis P symmetry is arranged that end of incoming cables LA, the LB of electric network power line, LC and zero line N and ammeter body pick out leading-out terminal OA, OB, OC and zero line N to user load, can reach like this and save material and dwindle the technique effect of ammeter bulk volume and weight.
Further, with reference to Fig. 4, described Acquisition Circuit 201,202 and 203 comprises copper-manganese divided circuit and isolation sensor U5, U6, U7, described terminals are connected to input end IAP, IAN, IBP, IBN, ICP, the ICN of copper-manganese divided circuit, the output terminal access isolation sensor U5 of described copper-manganese divided circuit, U6, U7.
Further, with reference to Fig. 6, described ammeter body comprises cooperatively interact fenced upper shell 10 and lower house 20, and described upper shell 10 is connected with lower house and has been defined the terminals that are used for connecting electric network power line and electrical network user load.
Further, described upper shell and lower house are respectively equipped with the zigzag auxiliary section 11 and 21 that mutually coincide.
Further, with reference to Fig. 7, in the preferred embodiment of the utility model three-phase intelligent ammeter, described zigzag auxiliary section 11 or 21 fleam are 113 °.
Further, described zigzag auxiliary section 11 or 21 sawtooth lateral length are 4.5mm, and vertically width is 1.5mm.
This jagged technical scheme that the utility model is advocated is according to drawing through repetition test and test in the technology implementation process, at first, zigzag of the present utility model auxiliary section 11 and 21 fleam are made as between 90 ° to 130 °, zigzag auxiliary section 11 and 21 sawtooth lateral length are made as between the 3mm to 6mm, and vertically width is made as between the 1mm to 3mm.Adopt the ammeter body of this technical scheme, when receiving extraneous electricity filching behavior, it is the suffered stress minimum in bonding part between the watchcase 10 and 20 up and down, and this kind design saves material cost the most, has avoided simultaneously distortion and the wearing and tearing of watchcase bonding part.
In general, guaranteeing that the ammeter single chip part has enough input current I
1After satisfying normal operation and requiring, voltage dropping power supply is remaining only the electric current of tens milliamperes even several milliamperes, and so how utilizing this part electric current then is a technical barrier.These seem useless electric current after through the design of the utility model preferred circuit, can be used effectively.In a preferred embodiment of the present utility model, this programme adopts sampling resistor+74HC14 not circuit chip+DC/DC Switching Power Supply to realize.74HC14(or 74HC04) the not circuit chip is the most frequently used, the most applicable digital circuit chip, oneself power consumption have 6 not gates in the uA level; Because of itself the high/low judgement voltage characteristic (the B step voltage than triode will be used well) that is constant, and output power can reach 20mA, can replace triode (saving current-limiting resistance).Cost is very low in addition, can contribute for the Cost Design that falls of whole electric energy meter; After using this not gate chip, when the mu balanced circuit of designing power supply rear end, can use wherein remaining several not circuits to replace conventional voltage stabilizing chip MC34063, save more costs.
Below will be take concrete phenotype as example, how each milliampere of maximum using electric current is finished some sophisticated functionss to the several voltage dropping power supply scheme with power stage control of describing the aforementioned techniques scheme in detail.Existing a electric energy meter possesses Long-distance Control switching on/(relay) function, and uses super capacitor to replace lithium battery to realize the power supply that has a power failure and show.Therefore the power supply of the utility model voltage dropping power supply scheme just is divided into four parts,
P
MAX=U
TVS·（I
1+I
2+I
3+I
4+I
D）
U
TVSBe the output voltage after the step-down process TVS clamper.
P
MAXMaximum output current is I under the input U for step-down externally exchanges
MAXThe time peak power output.
P
MAX=I
MAX·U
TVS
I
DElectric current for sampling resistor and 74HC14 consumption itself belongs to fixed loss.
Power supply at first guarantees the required input current I of ammeter single chip part normal operation
1
Use constant current I
2Power supply electric capacity in the relay switching on/circuit is charged, can realize relay switching on/function according to MCU Instruction after being full of electricity; Spend in actual applications 10S to be full of with 0.1s and be full of not significantly difference, the slightly long realization that does not affect the electric energy meter switching on/function of duration of charging, relay is drawn/closed to current international standard also failed call ammeter at once once powering on; In addition, when power supply after electric capacity is full of electricity, I then
2Be 0.Milliampere level constant-current charge is that the mode with triode+sampling resistor realizes that not only charging rate is faster than the mode that directly adds current-limiting resistance; And can be along with the rising of capacitance voltage as using current-limiting resistance, charged electrical fails to be convened for lack of a quorum more and more less and causes original minute 1mA or 2mA to only have at last 0.1mA in the situation of filling to capacitor charging, and charge efficiency is higher.
Adopt super capacitor to replace lithium battery to realize the aobvious power supply of power failure wheel of ammeter in this table.Because ammeter can not be in power down mode for a long time, according to the relevant criterion requirement, the time that super capacitor is full of electricity can reach 2 hours.Power supply is with all the residual current (I except front two parts electricity consumption
3=I
MAX-I
1-I
D) all distributed to the super capacitor charging circuit, be a milliampere level charging equally.Higher and save cost for charge efficiency, this table has adopted modal MC33063(or MC34063) mode of DC/DC chip+inductance forms reduction voltage circuit and realizes charging to super capacitor.After super capacitor is full of electricity, I
3Also be 0.
The 4th part is the TVS bleeder circuit, is used for when super capacitor and switching on/power supply electric capacity all are full of electricity unnecessary electric current I
4Consume, burn the voltage stabilizing chip of power supply front end in order to avoid voltage rises.
By above detailed description, can find out that the voltage dropping power supply scheme that this kind controlled with power stage can when realizing that traditional voltage dropping power supply scheme is the electric energy meter singlechip function of supplying power, also can realize following functions:
1, also can be the power supply capacitor charging of switching on/relay; And compared with the situation of transformer frequency response scheme for the power supply capacitor charging, normal switching on/relay (transformer frequency response scheme when 0.5Un normally switching on/relay) in the time of can being implemented in input voltage and being low to moderate 0.5Un.
2, for the super capacitor charging, replace lithium battery, traditional voltage dropping power supply scheme can't realize this function.
But voltage dropping power supply scheme widespread use in multifunctional electric energy meter that this kind controlled with power stage, and be very effectively to fall the cost power source design.
The first embodiment of the utility model reduction voltage circuit is a kind of buck DC-DC circuit.DC-DC output power of circuit P
Out=P
In* efficient.Reduction voltage circuit is the constant current source form, and peak power output is I * U, and wherein I is the electric current of constant current source.Such as 390nF electric capacity commonly used, at 230V, output current is 13mA during 50Hz.If use traditional linear voltage stabilization chip, such as 78L05(quiescent dissipation 2mA) when 230V, can obtain 5V, the power of 11mA.HT7533 (quiescent dissipation 2uA) can obtain the peak power output of 3.3V 13mA.Efficiency eta satisfies relational expression
V wherein
gFor supplying with the operating voltage of ammeter single-chip microcomputer, P
DBe the bypass consumed power.
Another characteristics of the utility model reduction voltage circuit are that output current is directly proportional with voltage, for example 230V time output 13mA.Output 9.1mA during 70%Un voltage.
The 3 copper-manganese sampling plan consumed powers of the utility model 71M6543 are approximately 3.3V, 20mA.When using traditional step-down+linear power supply can't satisfy the demand that under 84V AC, works.At 84V, can export 5.7mA during 60Hz.
This programme adopts chip MP2451.Quiescent current is much better than the 2mA of traditional MC33063 family chip much smaller than 0.5mA.Chip maximum working voltage 36V, limiting voltage 40V.For the peak power output that obtains, the voltage stabilizing diode clamping voltage is got 32V.Chip can obtain 85% efficient when 20mA exports.Calculate 84V, maximum output current under the 60Hz (output 3.3V) 32 * (5.7-0.5) * 0.85/3.3=43mA.Satisfy the demand of 20mA fully.Minimum input voltage can reach 45V AC.
The 71M6103 isolation sensor under RS485 conditions of demand useless, the advantage of the relative transformer of step-down:
1, output voltage is relevant with voltage stabilizing diode, and transformer and input voltage are proportional, and output voltage increases in doing 1.9 times of withstand voltage tests, often needs to increase the voltage stabilizing diode clamp.The large voltage stabilizing diode that burns easily of output energy when the transformer output power is large.Transformer is 84V output 3.3V in above-mentioned requirements, and in the situation of 20mA, 230V output reaches more than the 9V, and the 45V 230V voltage of can working need to reach 17V.And
2, output power and voltage are proportional, and transformer output power P
OutSquare proportional P with voltage U
Out~ U
284V output 3.3V in the above-mentioned situation, in the situation of 20mA, output 20mA voltage ratio 9V is much much higher during 230V.
3, device specification is few: in non-isolation ammeter, this reduction voltage circuit can use at 45V-240V, in 50Hz and the 60Hz circuit.And each voltage of transformer, frequency specification all needs several transformers to use, and versatility is 0 substantially.On cost contrast
Step-down scheme: single-phase meter: voltage stabilizing diode+electric capacity+resistance+MP2451+ inductance,
Three-phase meter: voltage stabilizing diode+3 (electric capacity+resistance)+MP2451+ inductance
Transformer: single-phase meter: transformer+linear voltage stabilization chip
Three-phase meter: 3 transformer+linear voltage stabilization chips.
Step-down scheme cost is far below transformer, and when the number of phases was many, transformer scheme need to increase transformer, and the step-down scheme only need to increase the prime capacitance-resistance, and the cost gap is obvious.
Expansion: for the flourish reduction voltage circuit of non-isolation ancestral.The chip for using in the medium-sized DC-DC circuit that uses previously.Withstand voltagely generally be lower than 36V.Also have in addition the withstand voltage DCDC chip of 72V, can export higher electric current through after the step-down.
Aforementioned being described in the non-buffer circuit used reduction voltage circuit.In the reduction voltage circuit chip of now conventional use, the efficient of part can reach more than 80% about 10mA.Because power consumption generally about 10mA, generally can reach 80﹠amp in the ammeter scheme in 10mA output situation; The chip of above efficient is few, and a lot of chips are often wanted just can reach more than 80% more than the 100mA, have lost meaning.
The another kind of reduction voltage circuit embodiment of the utility model reduction voltage circuit: its topological input voltage can be higher than output voltage, also can be equal to or less than output voltage.And limited at this input current of step-down, only need input voltage to be higher than the application of output voltage in the application that needs to use high input voltage to export large electric current through DC-DC.
The technical scheme of the utility model reduction voltage circuit is equally applicable to reverse excitation circuit (FLYBACK).On the switch power module of reverse excitation circuit main use in ammeter and on the insulating power supply.It is simple that the reverse excitation circuit of applicable technical solutions of the utility model has a circuit, the advantage that input range is wide.
Use another kind of reduction voltage circuit as insulating power supply but not this very ripe insulating power supply of circuit application in step-down of inverse-excitation type, chief reason is to use reverse excitation circuit at output 3.3V, 10MA, 485 tunnel output 5V, efficient can only reach about 30% in the situation of 1-10mA.Light-load efficiency, this is to make those skilled in the art use the problem of the Switching Power Supply headache of inductance, is difficult to accomplish more than 90% in existing semiconductor technology and switch knowledge at least.In line with the principle of the every 1mA that uses step-down to obtain as far as possible, do insulating power supply at 3.3V with another kind of reduction voltage circuit, 10MA, the 485 tunnel output 5V, 1-10mA(gets 5mA) situation under efficient can reach 65%.By using 390nF electric capacity, 2 times of current circuits are 50Hz, the design of output 26mA in the 230V situation, and clamping voltage 16V design, minimum operating voltage can reach 50V, the actual transformer (generally can only reach about 120V) that uses about 1W that is much better than.Use higher clamping voltage can also reach larger output power.
Use MP1542, value its band EN pin, can accomplish to restart when control inputs voltage reaches certain voltage, traditional MC33063 is not with the EN pin.Highest frequency can reach 1.3M, and the number of turn that the high-frequency transformer of use needs seldom is conducive to reduce the cost of high-frequency transformer.But its maximum 24V input is somewhat low, if use the available output power of chip of the maximum input of 36V larger.
Step-down scheme: single-phase meter: electric capacity+resistance+2 times current circuit+MP1542+ high-frequency transformer,
Three-phase meter: 3 (electric capacity+resistance)+MP1542+ high-frequency transformers.
Transformer: single-phase meter: transformer+arrangement+2 route voltage stabilizing chips
Three-phase meter: 3 transformer+arrangement+2 route voltage stabilizing chips.As seen step-down scheme cost is lower than transformer, and when the number of phases was many, transformer scheme need to increase transformer, and the step-down scheme only need to increase the capacitance-resistance of front, and the cost gap is obvious.
Relay is as the Some features of a load:
1: do not work under the normal conditions, just move in the time of need to operating a switch.The electric current that consumes at ordinary times is 0, and the electric current when operating a switch can reach 100mA, 200ms.
2: input voltage is had requirement, and the operation voltage of 9V for example is just can not regular event when if input voltage is lower than 6V.Normally stable under the general situation of maximum voltage.
Further describe again transformer and the step-down characteristics in relay is operated a switch circuit
Transformer:
Advantage: the relative step-down of output power wants large when rated voltage, and is short to the duration of charging of storage capacitor.Electric current during the actuating of relay is provided together by transformer and storage capacitor.
Shortcoming: output voltage changes with input voltage, and faster (consider that the single-chip microcomputer power requirement is constant, transformer has internal resistance) that output voltage reduces when input voltage reduces often can not be operated a switch because voltage is inadequate when needing wide region to operate a switch smoothly.
Step-down:
Advantage: output voltage does not change with input voltage.As long as the work of monolithic function just can be operated a switch.Transformer can be designed into input such as 2 above designs and can operate a switch when the 45V, and if will also can be operated a switch circuit with regard to more complicated under this voltage.Need to boost.
Add 485 to reduction voltage circuit, relay.Step-down is as the circuit of constant current source character.Electric current I is constant, by ammeter the electric current of using up has been wasted by voltage stabilizing diode or TVS.So how to utilize this part electric current, guarantee that again the circuit that self must always work obtains enough electric currents simultaneously.This will adopt power output control circuit.
The utility model power control control circuit is to make good use of each milliampere electric current that reduction voltage circuit provides.Realize with sampling resistor+comparer+switch.But the LM393 that comparer is commonly used slatterns the 1mA electric current again, and chip itself needs cost, therefore uses 74HC14(or 74HC04), this circuit with not gate characteristic can be the digital circuit chip that best embodies advantage.Cost is lower, and oneself power consumption has 6 not gates in the uA level, can replace triode (having save simultaneously current-limiting resistance).The On/Off voltage stabilization of utilization itself (the B step voltage than triode will be used well), output power can reach 20mA.Wave generator circuit can use 74HC14.
And in preferred embodiment of the present utility model, can further substitute unnecessary not gate with triode, so that it is less to take up room, price own can further reduce.
Tens milliamperes even several milliamperes electric current how distributing step-down to obtain must guarantee that at first single chip part needs enough input currents to come work.Relay a little slower that charging capacitor in the circuit can fill of operating a switch, flower 10S has no difference when being full of and being full of actual use with 0.1s.If accelerate the charging rate of charging capacitor, resistance in series is comparatively complicated, because along with the rising of capacitance voltage, charged electrical fails to be convened for lack of a quorum more and more less, the duration of charging is just elongated.And at this moment design for example divide 1mA or 2mA just only has 0.1mA being used for charging to the preferably discovery of capacitor charging.The constant-current charging circuit design is connected then comparatively complicated.Therefore the utility model uses the mode of triode+sampling resistor to carry out constant current.So that charging rate is obviously accelerated, and do not waste the electric current of any 1mA like this.
By loading super capacitor (1F's or higher), how controlled the duration of charging is again, and how longer is serviceable life? the charging of little electric current crossing current is better method.The crossing current circuit of front has all been distributed to the super capacitor charging circuit to the electric current that uses except system.Most economical reliable in order to charge, use reduction voltage circuit that super capacitor is charged, be to use MC33063+ inductance commonly used in order to save cost.
Simultaneously, the utility model proposes a kind of three-phase intelligent ammeter with novel power source design based on the technical scheme of describing in detail before, and the preferred implementation of three-phase intelligent ammeter of the present utility model is:
Use register to replace traditional LCD or electronic type display, this scheme cost is minimum, and service time is the longest.The register table is still larger in current technical field demand two.ADE7755 and ADE7752 are the single-phase electric meter comparatively commonly used and the computation chip of three-phase register formula ammeter scheme.
Single-phase register formula ammeter uses copper-manganese sampling+7755 classes chip+step-down power supply.
Three-phase register formula ammeter uses 3 CT+ADE7752 class chips+step-down power supply.More than current requirements 100A, and when needing anti-DC component, CT obviously is not first-selected technical scheme.That uses 3 copper-manganeses is the minimum sampling plans of home costs.
The copper-manganese scheme is not isolated.How in three-phase meter, to use.The utility model utilizes 71M6543 to provide a solution: current sample uses independently adc circuit, and the power supply of middle use pulse transformer adds communication.Must drive by 5V but drive register, so also need to increase again 5V power supply and not gate chip.It is also higher than liquid crystal scheme to increase a register scheme cost.
Adopting 3 road computation chips to gather the power that the sampling of 3 road copper-manganeses records, is a feasible scheme issue single-chip microcomputer by isolation.Here adopt 7021C class chip.
The single-chip microcomputer of 3 road copper-manganeses sampling+3 road 7021C+3 optocoupler carry high frequency pulse+1 is sent out pulse and is driven register after doing the pulse homogenising on the hardware.Serial ports by single-chip microcomputer itself is realized software regulating meter.
At first will solve the problem of metering, what A, B, C three-phase current voltage transmission were come is high-frequency impulse, output pulse after n high-frequency impulse is cumulative, m pulse rear drive register action.
If JA represents to export 1 pulse after JA pulse of A phase, the JB of existence, JC are arranged in like manner.Then close in the situation of phase and be exactly (if at this moment the umber of pulse of A, B, C is respectively a, b, c)
A/JA+b/JB+c/JC=1; It is too large to relate to floating number operand concerning 8 single-chip microcomputer.In the face of 240V, the situation of 120A can't be calculated at all, needs a kind of algorithm that is fit to 8 single-chip microcomputers.
a/JA+b/JB+c/JC=1。Both sides all be multiply by JA*JB*JC and are obtained
aJBJC+bJAJC+cJAJB=JAJBJC
So just there has not been the computing of floating number.Obtain a pulse of A phase with regard to cumulative upper JBJC, the like.Pulse of output when cumulative number surpasses JAJBJC.Computing is successively at 10us when single-chip microcomputer is 8M like this, and that can follow is upper.
Adopting another benefit after cumulative like this is that to do compensation very convenient, only needs to add compensation rate in accumulated value and gets final product.Compensation rate is by the adc circuit collection, and in order to calculate faster, compensation rate is 8 figure places.Can be for voltage, temperature compensates.
This programme has been furtherd investigate the characteristics of traditional another kind of reduction voltage circuit and the possibility that band isolation output is transformed, an afterflow inductance in the another kind of reduction voltage circuit is changed into isolating transformer, increased by one road spacing output circuit, thereby realized the Voltage-output of another kind of reduction voltage circuit band isolation, realized in band RS485 communication electric energy meter, adopting the voltage dropping power supply scheme.Through debugging and repetition test, adopt the band RS485 communication electric energy meter of this kind scheme when the 70V-400V wide region is inputted, to work, and passed through EMI and two heavyweight tests of EMC of GB and IEC relevant criterion.
Adopt the band RS485 communication electric energy meter of this kind voltage dropping power supply scheme have cost low, take up room little, highly low, use copper material few, lightweight, save the advantages such as effective, meritorious low in energy consumption, the wide range input of metal material, anti-strong magnetic, low-voltage switching on/, specifically describe as follows:
1, for being with 485 communication electric energy meters, this kind voltage dropping power supply scheme cost is far below transformer+rectifier bridge+voltage stabilizing chip power scheme (and transformer is large because using a large amount of copper cash and siliconized plate appreciated by non-ferrous metal to affect) with based on the AC/DC Switching Power Supply scheme of FLYBACK.Be applied in the single-phase meter, the cost of this power source design is about 2/3 of transformer scheme, is about 1/3 of FLYBACK scheme; Be applied in the three-phase meter, the cost of this power source design is about 2/5 of transformer scheme, is about the FLYBACK(inverse-excitation type) scheme 1/5.
2, this kind voltage dropping power supply scheme height and account for PCB area, weight all less than transformer scheme and FLYBACK scheme, can make electric energy meter to go out structure compacter, succinct and attractive in appearance.
3, wide range input can work under 70-400V voltage initial conditions.Transformer scheme needs to adopt for different frequency, electric current and voltage specification the transformer of different size; The FLYBACK scheme need adopt high withstand voltage metal-oxide-semiconductor, can not adopt conventional chip.
4, the isolating transformer of this voltage dropping power supply scheme employing only needs 2 groups of coils to get final product, and frequency can be compared with transformer scheme up to more than the 1MHz, and less coil and magnetic core have been saved metal material.
5, the isolating transformer of this voltage dropping power supply scheme does not need picture FLYBACK scheme store electricity energy for the RS485 communication when switch turn-offs, but directly be the RS485 power supply in switch closure, avoided under strong magnetic interference, causing because magnetic core is saturated can not stored energy problem, therefore anti-strong magnetic effect is better than the FLYBACK scheme.
6, the meritorious power consumption of this voltage dropping power supply scheme approximates the power input of another kind of step-down front end, without the middle core loss of similar transformer scheme existence; Simultaneously, the DC side of this voltage dropping power supply scheme, the input, output pressure reduction little, compare with the FLYBACK scheme, switching loss is little; Based on above 2 points, this voltage dropping power supply scheme has meritorious advantage low in energy consumption.
7, in the transformer scheme, output voltage is directly proportional with input voltage, crosses because of output voltage when input voltage is equal to or less than 50%Un and lowly can't finish the action of operating a switch; This voltage dropping power supply scheme does not change with input voltage because of output voltage, therefore all can finish the action of operating a switch in the full operating range of electric energy meter.Compare with the conventional transformer scheme, this voltage dropping power supply scheme has conclusive advantage.
Being preferred implementation of the present utility model only below, is not to be restriction to technical solutions of the utility model, and voltage dropping power supply scheme of the present utility model is applicable to any electronic type, comprises that intellectual ammeter uses.Simultaneously, the functional unit that only will be referred to the utility model detailed technology scheme in the accompanying drawing shows, and is not all elements of the whole circuit of statement.Should be understood that all modifications of having done based on technical solutions of the utility model, alternative or variation all should be covered by in the technical spirit of the utility model claims restriction.
Claims (14)
1. the power circuit of intelligent electric meter, it is characterized in that: comprise power output control circuit, reduction voltage circuit, ON-OFF control circuit and charging circuit, the input end of described reduction voltage circuit and output terminal are connected to the terminals of ammeter and the input end of ON-OFF control circuit, the output terminal access power output control circuit of described ON-OFF control circuit.
2. the power circuit of intelligent electric meter as claimed in claim 1, it is characterized in that: described reduction voltage circuit comprises from input end to output terminal RC circuit parallel with one another, from input end respectively with these RC circuit and the voltage dependent resistor (VDR) that connects and twin zener dioder, and be connected in mu balanced circuit between RC circuit and the output terminal; Perhaps described reduction voltage circuit comprises RC circuit, convection current diode and the electric capacity that is electrically connected successively from input end to output terminal, the TVS pipe, resistance, triode and the convection current diode that are electrically connected successively from input end to output terminal.
3. the power circuit of intelligent electric meter as claimed in claim 1, it is characterized in that: described ON-OFF control circuit comprises a control chip, it is electrically connected to the output terminal of reduction voltage circuit, and comprises a charging circuit, the output terminal access power output control circuit of described charging circuit; Perhaps
Described ON-OFF control circuit comprises a control chip and a spacing output circuit that is electrically connected with it, and further comprises a charging circuit, the output terminal access power output control circuit of described charging circuit.
4. the power circuit of intelligent electric meter as claimed in claim 1, it is characterized in that: described power output control circuit comprises impulse output circuit, suppresses circuit I, suppresses circuit I I and bleeder circuit, and described impulse output circuit is electrically connected with inhibition circuit I, inhibition circuit I I and bleeder circuit respectively.
5. such as the power circuit of each described intelligent electric meter of claim 1 to 4, it is characterized in that: the power that described ammeter power circuit produces satisfies relational expression PMAX=UTVSIMAX, wherein UTVS is reduction voltage circuit through the output voltage after suppressing circuit I and suppressing circuit I I clamper, and PMAX is the externally peak power output during the lower maximum output current IMAX of alternating voltage input of reduction voltage circuit.
6. the power circuit of intelligent electric meter as claimed in claim 5, it is characterized in that: IMAX=I1+I2+I3+I4+ID, wherein I1 is the working current of ammeter, I2 is the charging current that is dispensed to the switching on/electric capacity of ammeter, I3 is the charging current that is dispensed to charging circuit, I4 is discharge current, and ID is the by-pass current of ammeter power circuit.
7. the power circuit of intelligent electric meter as claimed in claim 6 is characterized in that: after switching on/electric capacity was full of electricity, I2 was zero, and after the charging circuit charging finished, I3 was zero.
8. three-phase intelligent ammeter, it comprises an ammeter body, be provided with several terminals in described ammeter body interior, processor, display circuit, communicating circuit and storer, and bring in by described wiring and to be arranged between mains supply line and the electrical network user load, it is characterized in that: further be provided with such as the described ammeter power circuit of any one in the claim 1 to 7,3 Acquisition Circuit and 3 computation chips, wherein said terminals are connected to respectively Acquisition Circuit and ammeter power circuit, described Acquisition Circuit is electrically connected to computation chip, described processor respectively with computation chip, the ammeter power circuit, display circuit, communicating circuit and storer are electrically connected.
9. three-phase intelligent ammeter as claimed in claim 8, it is characterized in that: described terminals are arranged with the symmetrical expression mode of connection.
10. three-phase intelligent ammeter as claimed in claim 8, it is characterized in that: described Acquisition Circuit comprises copper-manganese divided circuit and isolation sensor, described terminals are connected to the input end of copper-manganese divided circuit, the output terminal access isolation sensor of described copper-manganese divided circuit.
11. three-phase intelligent ammeter as claimed in claim 8 is characterized in that: described ammeter body comprises cooperatively interact fenced upper shell and lower house, and described upper shell has been connected the terminals that are used for connecting electric network power line and electrical network user load with lower house.
12. three-phase intelligent ammeter as claimed in claim 11 is characterized in that: described upper shell and lower house are respectively equipped with the zigzag auxiliary section that mutually coincide.
13. three-phase intelligent ammeter as claimed in claim 12 is characterized in that: the fleam of described zigzag auxiliary section is made as between 90 ° to 130 °.
14. such as claim 12 or 13 described three-phase intelligent ammeters, it is characterized in that: the sawtooth lateral length of described zigzag auxiliary section is made as between the 3mm to 6mm, vertically width is made as between the 1mm to 3mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220314060 CN202693675U (en) | 2012-06-27 | 2012-06-27 | Power circuit for intelligent electric meter and three-phase intelligent electric meter with power circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220314060 CN202693675U (en) | 2012-06-27 | 2012-06-27 | Power circuit for intelligent electric meter and three-phase intelligent electric meter with power circuit |
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| CN202693675U true CN202693675U (en) | 2013-01-23 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102798756A (en) * | 2012-06-27 | 2012-11-28 | 华立仪表集团股份有限公司 | Power supply circuit for intelligent electricity meter and three-phase intelligent electricity meter |
| CN103389396A (en) * | 2013-07-09 | 2013-11-13 | 华立仪表集团股份有限公司 | Single-phase register ammeter with far infrared communication function and registering method thereof |
| CN103997203A (en) * | 2014-05-28 | 2014-08-20 | 国家电网公司 | Power circuit of electric distribution device temperature rise monitoring device |
-
2012
- 2012-06-27 CN CN 201220314060 patent/CN202693675U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102798756A (en) * | 2012-06-27 | 2012-11-28 | 华立仪表集团股份有限公司 | Power supply circuit for intelligent electricity meter and three-phase intelligent electricity meter |
| CN103389396A (en) * | 2013-07-09 | 2013-11-13 | 华立仪表集团股份有限公司 | Single-phase register ammeter with far infrared communication function and registering method thereof |
| CN103389396B (en) * | 2013-07-09 | 2016-04-13 | 华立科技股份有限公司 | A kind of single-phase register ammeter and metering method thereof with Far-infrared communication function |
| CN103997203A (en) * | 2014-05-28 | 2014-08-20 | 国家电网公司 | Power circuit of electric distribution device temperature rise monitoring device |
| CN103997203B (en) * | 2014-05-28 | 2017-03-15 | 国家电网公司 | The power circuit of distribution net equipment temperature rise monitoring device |
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Granted publication date: 20130123 Termination date: 20130627 |