CN202309092U

CN202309092U - Embedded low-power in-situ reactive compensation device

Info

Publication number: CN202309092U
Application number: CN 201120436847
Authority: CN
Inventors: 黄有全
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-11-08
Filing date: 2011-11-08
Publication date: 2012-07-04
Anticipated expiration: 2021-11-08

Abstract

The utility model relates to an embedded low-power in-situ reactive power compensation device which comprises a microcontroller unit (1), a current zero-crossing point detection unit (3), a voltage zero-crossing point detection unit (2), a compensation capacitor switching interface unit (8) and three groups of compensation capacitors (5, 6 and 7), wherein the voltage at the two ends of a load is input into the voltage zero-crossing point detection unit by a voltage transformer for detecting the zero point of voltage; the current of the load is input into the current zero-crossing point detection unit by a current transformer for detecting the zero point of current; zero-crossing point signals of the voltage and the current are input into a port of the microcontroller unit; after the zero-crossing point signals of the voltage and the current are compared and calculated in a microcontroller, the phase difference between the current and the voltage can be acquired; and the power factor is measured, and the compensation capacitors are connected to the two ends of the load when the voltage is at the zero-crossing point according to the phase difference between the current and the voltage. The embedded low-power in-situ reactive compensation device can be installed at a low-power terminal user in an in-situ way, and can be embedded into an electric energy meter or an inductive domestic appliance to be taken as a composition part of the electric energy meter or the inductive domestic appliance, so that reactive compensation can be directly carried out at the place where the electrical appliance is arranged by the device, and the best energy-saving effect can be achieved.

Description

Embedded small-power is reactive-load compensator on the spot

Technical field

The utility model relates to a kind of embedded small-power idle compensating control on the spot.Be mainly used in single-phase small-power in-situ reactive power compensation, be used in particular for rural area small-power in-situ reactive power compensation.Belong to energy-conservation, lower consumption and optimize the automation control area of the electrical network quality of power supply.

Technical background

Carrying out reactive power compensation in the electrical network generally is in one-level transformation and secondary transformation distribution, to carry out centralized compensation.Because aspects such as compensation costs, the less terminal distribution line of diameter of wire huge for quantity, circuit does not carry out reactive power compensation, and the line loss that reactive power causes is very big.In the reactive power compensation, near the terminal use, the energy-saving effect of compensation is good more.Along with China's growth in the living standard, domestic consumer's power consumption increases substantially, and inductive loads such as high-power electric appliance such as air-conditioning, washing machine, refrigerator are popularized in the city.Along with the household electrical appliances implementation of preferential policy such as go to the countryside, the electrical equipment popularity in rural area also improves very fast.The distributed cheaply small-power reactive-load compensator that is embedded in family or the inductive household electrical appliance can be filled up the blank of the terminal reactive power compensation of electrical network, and extremely wide application prospect and high economic worth are arranged.

Summary of the invention

The purpose of the utility model be to provide a kind of can be to single-phase small-power user and the electrical appliance embedded in-situ reactive power compensating controller that distributes.

[0003] technical scheme of the utility model is described below:

Embedded small-power is reactive-load compensator on the spot, comprises micro controller unit (1), point of zero voltage detecting unit (2), current zero detecting unit (3), compensation condenser switching driving interface circuit (8), three compensation condensers (5,6,7), power subsystem (4).Fig. 1 is the embedded small-power structural representation of reactive-load compensator on the spot.Through the time difference between electric current on the sensing lead and the voltage over zero, record the power factor (PF) of load.

Described embedded small-power reactive-load compensator on the spot comprises microprocessor controls unit (1).The microprocessor controls unit is a control centre with the STC12C5410 microcontroller; From the P32 of microcontroller and the current zero signal and the point of zero voltage signal of P33 port input load; With the time difference that the high-speed counter of microcontroller is accurately measured current zero and point of zero voltage, calculate the power factor (PF) of load according to this time difference.When power factor (PF) is lower than set point, microcontroller will be connected on the two ends that building-out capacitor parallel connection on the capacitor switching interface circuit is linked into load automatically, turn-on time point at the zero crossing of voltage constantly, electric capacity inserts surge current and minimizes.Can drop into three groups of building-out capacitors at most.Prescribe a time limit when power factor (PF) reaches going up of setting, the capacitor that microcontroller will be linked into the load two ends automatically breaks off, and opening time, point was the zero crossing moment of voltage, avoided occurring overcompensation.

Described embedded small-power reactive-load compensator on the spot comprises point of zero voltage detecting unit (2).The elementary load two ends that are connected in parallel on of voltage transformer; Secondary voltage signal with load removes common mode interference signal through anti-jamming circuit; Amplifying circuit amplifies signal; Compare with no-voltage, output signal generation saltus step when load alternating current is pressed zero crossing is through being input to the P33 of microcontroller after waveform arrangement and the conversion.

Described embedded small-power reactive-load compensator on the spot comprises current zero detecting unit (3).Current transformer elementary is connected on the current supply line of load; Secondary current signal with load converts voltage signal into; Remove common mode interference signal through anti-jamming circuit, signal is amplified, compare with no-voltage through amplifying circuit; Output signal generation saltus step when load alternating current flows through zero point is through receiving the P32 of microcontroller after waveform arrangement and the conversion.

Because load is an inductive nature, between voltage and the electric current phase difference is arranged, the zero-crossing timing of electric current and voltage is different.Microcontroller is through measuring the time difference of electric current and voltage over zero, the power factor (PF) of computational load.

Described embedded small-power reactive-load compensator on the spot comprises driving interface circuit (8).Drive circuit adopts the photoelectricity coupling, and the microcontroller part that will be used for signal processing is isolated with the load compensation condenser network.Be convenient to carry out of input and the excision of dynamic compensation electric capacity from the load two ends.

Described embedded small-power reactive-load compensator on the spot comprises three groups of compensation condensers (5,6,7).Under the control of microcontroller, one group or two groups or three group capacitors are put in the compensating circuit.When the power factor (PF) of real-time measurement is lower than set point, drop into one group of compensation condenser, three groups of compensation condensers can put into operation simultaneously.When the power factor (PF) of real-time measurement is higher than set point, excise one group of compensation condenser, three groups of compensation condensers can not move, and avoid overcompensation.

Description of drawings

Below in conjunction with accompanying drawing the utility model is described further:

Fig. 1 is the utility model circuit block diagram;

Fig. 2 is the point of zero voltage testing circuit figure of the utility model;

Fig. 3 is the current zero testing circuit figure of the utility model;

Fig. 4 is three road building-out capacitors and the interface circuit figure thereof of the utility model.

Marginal data: among Fig. 2, Lu is a voltage transformer, and Rw1 is the signal magnitude regulator potentiometer, and A11, A12, A13 are operational amplifiers, and A14 is a comparator, and A15 is a Schmidt trigger.Among Fig. 3, Li is a current transformer, and A21, A22, A23 are operational amplifiers, and A24 is a comparator, and A25 is a Schmidt trigger.

Embodiment

Embedded small-power is the operation principle of reactive-load compensator on the spot:

Fig. 2 is the embedded small-power point of zero voltage testing circuit figure of reactive-load compensator on the spot.Be connected in parallel on the elementary voltage signal of obtaining load of the voltage transformer Lu at load two ends; From secondary output; Be connected on the potentiometer Rw1 of signal amplitude adjusting; Receive the in-phase input end of operational amplifier A 11 and A12 from the centre cap of Rw1 through input resistance R11 and R15, suppress common-mode signal and amplify difference mode signal, the input that is input to operational amplifier A 13 again carries out the signal amplitude amplification.Input and no-voltage that comparator A14 is received in the output of A13 compare, and when the power frequency ac voltage zero crossing, the output level of A14 is exported square wave when transition takes place, and the forward position of square wave is exactly the zero point of ac voltage signal.Be input to the P33 mouth of microcontroller after through Schmidt trigger A15 shaping from the square wave of A14 output, be used for microcontroller and measure power factor (PF).

Fig. 3 is the embedded small-power current zero testing circuit figure of reactive-load compensator on the spot.What be connected on current transformer Li on the load circuit elementaryly converts behind the voltage signal current signal into from current transformer secondary output; Process input resistance R21 and R25 receive the in-phase input end of operational amplifier A 21 and A22; Suppress common-mode signal and amplify difference mode signal, the input that is input to operational amplifier A 23 again amplifies.Input and no-voltage that comparator A24 is received in the output of A23 compare, when the industrial frequency AC current zero-crossing point, and the output level generation transition of A24, the output square wave, the forward position of square wave is exactly the zero point of ac current signal.Be input to the interruptive port of microcontroller after through Schmidt trigger A25 shaping from the square wave of A24 output, be used for microcontroller and measure power factor (PF).

The microprocessor controls unit is made up of STC12C5410 microcontroller, crystal, electrify restoration circuit.When being connected on the voltage over zero pulse generation level translation on the microcontroller port P33; Microcontroller picks up counting; When being connected on the current zero-crossing point pulse generation level translation on the microcontroller port P32, stop timing, through program correction timing error; The ratio of this time difference with the cycle of industrial-frequency alternating current is exactly the phase difference of load, calculates power factor (PF) with phasometer.When the power factor (PF) that records in real time is lower than set point, at next point of zero voltage constantly, from output port P13 or P14 or low level 0 of P15 output; Connect thyristor; The compensation condenser parallel connection is linked into the load two ends, carries out capacitance compensation, improve power factor (PF).When the power factor (PF) that records in real time is higher than set point, at next point of zero voltage constantly, from output port P13 or P14 or high level 1 of P15 output; Break off the thyristor control signal; Compensation condenser from load two tip cut-offs, is withdrawed from capacitance compensation, avoid overcompensation.

Fig. 4 is the embedded small-power output interface circuit and the compensation condenser of reactive-load compensator on the spot.Receive the base stage of triode Q31 through resistance R 31 from the control signal of microcontroller port P13.When the P13 of microcontroller output high level 1, triode Q31 ends, not conducting of photoelectrical coupler, and thyristor breaks off, and compensation condenser C31 is from load two tip cut-offs.When the P13 of microcontroller port output low level 0, triode Q31 conducting, the photoelectrical coupler conducting, the thyristor conducting, compensation condenser C31 is linked into the load two ends.Other two groups of compensation condenser interface control ends are connected on the P14 and P15 port of microcontroller, and control procedure is identical with first group control procedure.

Claims

1. embedded small-power reactive-load compensator on the spot; It is characterized in that: described embedded small-power reactive-load compensator on the spot comprises micro controller unit (1); Point of zero voltage detecting unit (2), current zero detecting unit (3), compensation condenser switching interface unit (8); Three building-out capacitor unit (5,6,7), power subsystem (4); The load voltage is received described point of zero voltage detecting unit (2) input through voltage transformer, and the crossover point signal that detects load voltage is received the P33 port of micro controller unit (1); Load current is received described current zero detecting unit (3) through current transformer, detects the P32 port that the current zero-crossing point signal is received micro controller unit (1); Record the phase difference between the crossover point signal of electric current and voltage through the inner counter timer of micro controller unit (1), obtain power factor (PF); According to power factor (PF) compensation condenser switching interface unit (8) is sent control signal, the voltage over zero of industrial-frequency alternating current next cycle constantly with one in three building-out capacitor unit or all parallel connection be linked into the load two ends.