CN2854671Y

CN2854671Y - Low-voltage reactive power automatic compensation controller

Info

Publication number: CN2854671Y
Application number: CNU2005200142189U
Authority: CN
Inventors: 李月军; 余意平; 潜智明
Original assignee: HANGSHEN HOLDING GROUP CO Ltd
Current assignee: HANGSHEN HOLDING GROUP CO Ltd
Priority date: 2005-08-19
Filing date: 2005-08-19
Publication date: 2007-01-03
Anticipated expiration: 2015-08-19

Abstract

The utility model discloses a low-voltage reactive power automatic compensation controller, which has a microprocessor as a core and comprises a zero detection circuit, a microprocessor MCU, a LCD/LED display circuit, and a compensation capacitor controlled output-river circuit. The utility model uses high-precision zero detection circuit to convert AC voltage and current to square wave signal to access the microprocessor to input capture pin, calculates the power factor and frequency through the microprocessor based on the time difference of the captured voltage and current signals rising to pass zero, calculates the voltage and current through A/D sampling, uses logical judgment ability of the microprocessor to automatically identify and adjust the current with the same phase and name, displays power factor value and voltage and current values, and controls the switch of the compensation capacitor based on the judgment of the power factor value, voltage value and current value.

Description

Low-voltage reactive power power automatic compensating controller

One. technical field

The utility model relates to a kind of low-voltage reactive power power automatic compensating controller, belongs to the low voltage control Instrument technology field.

Two. background technology

Low-voltage reactive power power automatic compensating controller is widely used in the distribution system, and it regulates reactive current in the distribution by control compensation electric capacity, reduces the line loss that reactive current is brought, and energy savings is stablized line voltage, increases the effect of the capacity of transformer.Domestic by retrieval patent though find that low-voltage reactive power power automatic compensating controller patent is a lot, does not all have explanation that function and the solution that can discern and adjust electric current the same phase and name automatically arranged.Thus, cause a lot of products, need when wiring is installed, carry out manual adjustment, thereby increase the workload of wiring debugging work often because of reasons such as end sign mistakes of the same name.

Three. summary of the invention

For solving above-mentioned existing problems, the utility model provides a kind of low-voltage reactive power power automatic compensating controller that can discern and adjust electric current the same phase and name function automatically that has.

Low-voltage reactive power power automatic compensating controller described in the utility model, it is core with the microprocessor, is made up of mirror zero circuit, microprocessor MCU, display module, building-out capacitor control output driving circuit etc.To amplifying the square wave rising edge that produces after the AC signal by mirror zero circuit two-stage high power, the continuous rising edge of voltage square wave is gone out power cycle T and frequency along detection computations by its input capture pin along detection To voltage and current square wave rising edge along detection computations

Go out phase time difference t, according to formula:

T: the period measurement time, with two rising edge zero crossing mistimings of microprocessor CCP1 measuring voltage ripple

T: with the mistiming of voltage wave rising edge zero crossing (CCP1 seizure) between the current wave rising edge zero crossing (CCP2 seizure)

φ: the angle between voltage and the electric current can calculating voltage and electric current between angle phi, differentiate according to place, phasing degree quadrant then and adjust with the same door end, and the differentiation reactive current is perception or capacitive, calculate power factor value, controller then can come the switching of control compensation electric capacity according to control output driving circuit after the situation analysis such as the character of power factor (PF) value, reactive current, voltage and current size.

The utility model through after the above-mentioned design compared with prior art, has the following advantages:

1, the mirror zero circuit is made up of four anti-phase scale operation circuit, can obtain higher voltage enlargement factor and higher input resistance simultaneously under the unlikely too high situation of resistance in circuit, makes it can both obtain the high-precision power factor when different electric current.

2, utilize the input capture function of microprocessor and calculating arbitration functions to realize identification automatically and adjust electric current the same phase and name that hardware circuit is simple, economical.

Four. description of drawings

Accompanying drawing 1 is the circuit diagram of this novel practical

1---represents the zero circuit that reflects; 2---represents the square wave by the generation of mirror zero circuit;

3---represents to have the programmable microprocessor of input capture function;

4---represents display module; 5---represents building-out capacitor control output driving circuit

Accompanying drawing 2-7 is this novel practical rated output factor and voltage and current waveform figure when differentiating the fellow disciple and holding

Accompanying drawing 2: electric current is consistent with polarity of voltage, current waveform lagging voltage waveform, both mistiming t;

Accompanying drawing 3: electric current is consistent with polarity of voltage, current waveform leading voltage waveform, both mistiming t;

Accompanying drawing 4: current polarity connects instead, and the current wave of correct connection should be shown in the dotted line, and because of current polarity connects instead, current wave is shown in the solid line, and both concern current waveform leading voltage waveform, both mistiming t;

Accompanying drawing 5: polarity of voltage connects instead, and the voltage wave of correct connection should be shown in the dotted line, and because of polarity of voltage connects instead, voltage wave is shown in the solid line, and both concern current waveform leading voltage waveform, both mistiming t;

Accompanying drawing 6: current polarity connects instead, and the current wave of correct connection should be shown in the dotted line, and because of current polarity connects instead, current wave is shown in the solid line, and both concern current waveform lagging voltage waveform, both mistiming t;

Accompanying drawing 7: polarity of voltage connects instead, and the voltage wave of correct connection should be shown in the dotted line, and because of polarity of voltage connects instead, voltage wave is shown in the solid line, and both concern current waveform lagging voltage waveform, both mistiming t.

Five, embodiment:

Low-voltage reactive power power automatic compensating controller is a core with microprocessor MCU (3); Form by mirror zero circuit (1), display module (4), building-out capacitor control output driving circuit (5); Mirror zero circuit (1) is made up of four anti-phase ratio discharge circuits; Per two anti-phase ratio discharge circuits constitute one two step voltage and a two-stage current circuit respectively by coupled in series; Two step voltages and two-stage current circuit are respectively by diode D ₁, R ₉And D ₂, R ₁₉Be connected with microprocessor MCU (3).Each discharge circuit is respectively by three equivalent series resistance (R ₁/ R ₂/ R ₃, R ₅/ R ₆/ R ₇, R ₁₁/ R ₁₂/ R ₁₃, R ₁₅/ R ₁₆/ R ₁₇), a stake resistance R ₄, R ₈, R ₁₄, R ₁₈Form with an operational amplifier.Embodiment is that grid ac voltage and electric current are become the alternating voltage of small-signal and the A/D sampling pin that electric current inserts mirror zero circuit (1) and microprocessor MCU (3) respectively behind transformer and mutual inductor, and the output terminal of operational amplifier passes through T type feedback network (as R ₂/ R ₃/ R ₄) draw the inverting input of getting back to amplifier and constitute voltage negative feedback in parallel, can be according to amplifier enlargement factor computing formula as the discharge circuit in the empty frame:

This design can make in the discharge circuit resistance little and obtain high power and amplify and higher input resistance, can make simultaneously the mirror zero circuit that higher precision is arranged, amplifying AC signal by mirror zero circuit two stage amplifer high power makes it become square-wave signal, the square-wave signal that produces is sent into input capture function pin CCP1 and the CCP2 pin of microprocessor MCU after diode D1, D2 eliminate negative terminal, microprocessor (3) goes out power cycle T and frequency to the continuous rising edge of voltage square wave along detection computations by the CCP1 pin

By CCP1 and CCP2 pin voltage and current square wave rising edge is gone out phase time difference t along detection computations, according to formula Angle phi between calculating voltage and the electric current is differentiated according to place, phasing degree quadrant then and is adjusted with the same door end, differentiates reactive current and is perception or capacitive, calculates power factor value, and its method is as follows:

1 when φ≤90 °, and electric current is consistent with polarity of voltage, the electric current lagging voltage, and it is perceptual that reactive current is, and power factor value is COS φ; (seeing accompanying drawing 2)

2 when 90 °＜φ≤180 °, and electric current and polarity of voltage connect instead and the electric current leading voltage, and reactive current is capacitive, and power factor value is COS (φ-90 °); (seeing accompanying drawing 4,5)

3 when 180 °＜φ≤270 °, and electric current and polarity of voltage connect anti-and electric current lagging voltage, and it is perceptual that reactive current is, and power factor value is COS (φ-180 °); (seeing accompanying drawing 6,7)

4 when 270 °＜φ≤360 °, and electric current is consistent with polarity of voltage, the electric current leading voltage, and reactive current is capacitive, and power factor value is COS (φ-270 °) (seeing accompanying drawing 3)

Above-mentioned differentiation and calculating realize by microprocessor is programmed, microprocessor is being differentiated the same phase and name, in the time of idle attribute of electric current and rated output factor by the AD current voltage and current value of sampling, and with power factor value, the attribute of reactive current, magnitude of voltage and current value send display module (4) to show by the I/O mouth of microprocessor, microprocessor is according to the size of power factor value, reactive current is perception or capacitive, whether overvoltage of voltage, electric current has conditions such as the undercurrent of denying, I/O mouth by microprocessor drives the switching that building-out capacitor is controlled output driving circuit (5) building-out capacitor, makes the power factor (PF) of electrical network arrive optimum condition.

Claims

A kind of low-voltage reactive power power automatic compensating controller, it is characterized in that low-voltage reactive power power automatic compensating controller is a core with microprocessor MCU (3), form by mirror zero circuit (1), display module (4), building-out capacitor control output driving circuit (5), mirror zero circuit (1) is made up of four anti-phase ratio discharge circuits, per two anti-phase ratio discharge circuits pass through coupled in series, constitute one two step voltage and a two-stage current circuit respectively, two step voltages and two-stage current circuit are respectively by diode D ₁, R ₉And D ₂, R ₁₉Be connected with microprocessor MCU (3).