CN204243756U - A kind of photovoltaic generating system controlling harmonic wave - Google Patents

Abstract

A kind of photovoltaic generating system controlling harmonic wave, comprise photovoltaic array, inversion unit, transformer, SVC device, described inversion unit controller calculates reactive power Q 1 according to the photovoltaic array DC side current value gathered, photovoltaic array DC side current value is converted to the standard signal of 4-20mA, input to SVC controller; Described SVC device comprises compensation reactor, FC filter branch, SVC controller, compensation reactor, FC filter branch are connected with electrical network bus respectively, SVC controller is connected with inversion unit controller output end by connection, SVC controller is also connected with the voltage transformer of acquisition system busbar voltage Us and the current transformer of acquisition system inlet wire current Is by connection, and the circuit-breaker switching on-off signal of FC filter also inputs SVC controller.The utility model control structure harmonic controling is effective.

Description

A kind of photovoltaic generating system controlling harmonic wave

Technical field

The utility model relates to a kind of grid-connected technical field, particularly relates to a kind of grid-connected structure of carrying out harmonic controling.

Background technology

Photovoltaic plant converts the direct current energy of photovoltaic array to can send into electrical network alternating current, in the process that photovoltaic plant electric energy is connected to the grid, can produce harmonic wave to electrical network, affect the quality of electrical network.

The photovoltaic DC-to-AC converter of current domestic research and development meets grid-connected requirement substantially, the active power compensator of harmonic controling many employings external hanging type of output, and cost is high, and volume is large, and power consumption is high, can not meet the high requirement of user under intelligent grid.

Therefore, research and develop the photovoltaic generating system of Novel control structure, realize output current harmonics and compensate accurately fast, have very important meaning.

Utility model content

The purpose of this utility model is to provide a kind of photovoltaic generating system controlling harmonic wave, adopts the mode of compensation reactor and FC filter branch to compensate grid-connected harmonic wave, meanwhile, also contemplates photovoltaic array DC power supply to harmonic influence factor; The harmonic wave fine compensation to grid-connected photovoltaic system can be realized.

For achieving the above object, the utility model realizes by the following technical solutions:

A kind of photovoltaic generating system controlling harmonic wave, it is characterized in that, comprise photovoltaic array, inversion unit, transformer, SVC device, photovoltaic array output is connected to capacitor, another termination inversion unit of capacitor, inversion unit connects transformer, and transformer, capacitor C, reactor L, circuit breaker K1 connect successively, and circuit breaker K1 gets access to grid bus; Direct current collection point is provided with at the DC output end of photovoltaic array, by the current value input inversion unit controller that connection will gather, described inversion unit controller output pwm signal is to inversion unit, described inversion unit controller calculates reactive power Q 1 according to the photovoltaic array DC side current value gathered, photovoltaic array DC side current value is converted to the standard signal of 4-20mA, input to SVC controller;

Described SVC device comprises compensation reactor, FC filter branch, SVC controller, compensation reactor, FC filter branch are connected with electrical network bus respectively, SVC controller is connected with inversion unit controller output end by connection, SVC controller is also connected with the voltage transformer of acquisition system busbar voltage Us and the current transformer of acquisition system inlet wire current Is by connection, and the circuit-breaker switching on-off signal of FC filter branch also inputs SVC controller.

Compared with prior art, the beneficial effects of the utility model are:

Inversion unit controller sends PWM triggering signal, and the direct current of photovoltaic array is transformed into alternating current through inversion unit, and inversion unit calculates the reactive power that photovoltaic array produces simultaneously, and this reactive power Q 1 is transferred to SVC controller; The voltage of SVC controller acquisition system bus, system inlet wire current, and the circuit-breaker switching on-off situation considering filter branch, send control signal to compensation reactor.The utility model control structure harmonic controling is effective.

Accompanying drawing explanation

Fig. 1 is the structure principle chart of the utility model control method.

Fig. 2 is the control strategy block diagram of the utility model control method.

Fig. 3 is the structure chart of inversion unit.

Fig. 4 is the structure chart of inversion unit controller.

Embodiment

Concrete technology contents of the present utility model is described in detail below in conjunction with accompanying drawing.

The concrete structure composition of this device:

See Fig. 1, SVC device comprises compensation reactor, FC filter branch, SVC controller, the busbar voltage Us of SVC controller acquisition system and system inlet wire current Is, and the killer switch situation of FC filter branch, SVC controller also receives the reactive power signals Q1 that inversion unit controller exports; SVC controller considers above parameter, calculates reactive power compensation amount, realizes reactive power compensation by the mode controlling Trigger Angle.

Photovoltaic array output is connected to capacitor, another termination inversion unit of capacitor, and inversion unit connects transformer, and transformer, capacitor C, reactor L, circuit breaker K1 connect successively, and circuit breaker K1 gets access to grid bus; Direct current collection point is provided with at the DC output end of photovoltaic array, by the current value input inversion unit controller that connection will gather, described inversion unit controller output pwm signal is to inversion unit, direct current for being exported by photovoltaic array is transformed into alternating current, by transformer, voltage transition is become suitable magnitude of voltage input electrical network.

Fig. 3 is the structure chart of inversion unit, form two level PWM inversions with diode (D1, D2, D3, D4, D5, D6) inverse parallel respectively by six IGBT wholly-controled device (IGBT1, IGBT2, IGBT3, IGBT4, IGBT5, IGBT6), after inversion, signal inputs by capacitor C, reactor L LC filter branch in series through transformer.Reactor L another end is also connected to circuit breaker K1, and circuit breaker K1 is connected with electrical network bus.

Fig. 4 is inversion unit controller architecture sketch, controller is made up of fpga chip, cpu chip, A/D chip, voltage signal or current signal enter cpu chip after A/D conversion, enter fpga chip, the pwm control signal of power output unit after fpga chip process after cpu chip process.

SVC is idle, and control procedure is as follows:

When FC filter branch drops into, the idle amount that SVC need compensate increases, and TCR Trigger Angle diminishes, and exports corresponding lagging reactive power; On the contrary when after the excision of FC filter branch, the idle amount that SVC need compensate reduces, and TCR Trigger Angle becomes large, exports corresponding lagging reactive power and reduces.When the idle increase of photovoltaic array perception, the idle total amount that SVC need compensate reduces, and TCR Trigger Angle becomes large, exports corresponding lagging reactive power and reduces.If after predictive compensation, system reactive power occurs stablizing deviation, then PI governing loop starts, and eliminates the steady state error compensated.

In Fig. 2: Qfcn is the compensating power value of each FC filtering channel

Sfcn is the on off state of each filtering channel

Q1 is that inversion unit controller calculates reactive power output valve

Q is system inlet wire SVC reactive power compensation desired value

Qs is system inlet wire reactive power detection value

Us is system busbar voltage

Is is system inlet wire current value

The synthetic load of SVC equipment replacement is except comprising filter FC, photovoltaic array, also comprise other accessory power supply load be under same bussed supply, SVC equipment self adds integral adjustment in control mode, to ensure the stable state compensation effect of SVC compensator, the reactive power simultaneously also corrected due to photovoltaic array calculates the compensate that error causes.

See Fig. 1, Fig. 2, a kind of Harmonic Control Method of photovoltaic generating system, comprise following content:

1) photovoltaic array output is connected to capacitor, another termination inversion unit of capacitor, and inversion unit connects transformer, and transformer, capacitor C, reactor L, circuit breaker K1 connect successively, and circuit breaker K1 gets access to grid bus; Direct current collection point is provided with at the DC output end of photovoltaic array, by the current value input inversion unit controller that connection will gather, described inversion unit controller output pwm signal is to inversion unit, direct current for being exported by photovoltaic array is transformed into alternating current, by transformer, voltage transition is become suitable magnitude of voltage input electrical network; Described inversion unit controller also calculates reactive power Q 1 by the photovoltaic array DC side current value gathered, and this value is converted to the standard signal of 4-20mA, inputs to SVC controller;

2) SVC controller receives the reactive power Q 1 that inversion unit controller exports, and according to system busbar voltage U s and system inlet wire current Is, and the circuit-breaker switching on-off situation of FC filter branch, SVC controller considers above parameter, reactive power compensation amount is calculated, realizes reactive power compensation by the mode controlling Trigger Angle α;

3) control strategy: by the on off state detecting FC filter circuit breaker, SVC controller judges whether FC filter branch devotes oneself to work, when after FC filter branch breaker closing, Sfcn state is designated as 1; When after FC filter branch breaker open operation, Sfcn state value is 0; Then, after suing for peace by the reactive power fixed compensation amount that each FC filter branch quantity of state is multiplied by this branch road, the idle amount of each filter branch of FC is obtained; By PI regulative mode, export reactive power compensation amount.

Claims (1)

1. one kind can control the photovoltaic generating system of harmonic wave, it is characterized in that, comprise photovoltaic array, inversion unit, transformer, SVC device, photovoltaic array output is connected to capacitor, another termination inversion unit of capacitor, inversion unit connects transformer, and transformer, capacitor C, reactor L, circuit breaker K1 connect successively, and circuit breaker K1 gets access to grid bus; Direct current collection point is provided with at the DC output end of photovoltaic array, by the current value input inversion unit controller that connection will gather, described inversion unit controller output pwm signal is to inversion unit, described inversion unit controller calculates reactive power Q 1 according to the photovoltaic array DC side current value gathered, photovoltaic array DC side current value is converted to the standard signal of 4-20mA, input to SVC controller;

Described SVC device comprises compensation reactor, FC filter branch, SVC controller, compensation reactor, FC filter branch are connected with electrical network bus respectively, SVC controller is connected with inversion unit controller output end by connection, SVC controller is also connected with the voltage transformer of acquisition system busbar voltage Us and the current transformer of acquisition system inlet wire current Is by connection, and the circuit-breaker switching on-off signal of FC filter branch also inputs SVC controller.