CN201846230U - High-power capacitance type charging circuit using wind power converter for energy storage - Google Patents

Abstract

The utility model belongs to wind power generation equipment, and relates to a high-power capacitance charging circuit using a wind power converter for energy storage. The circuit comprises a ram side rectification circuit and a net side inversion circuit which are connected between a generator and a power grid; the ram side rectification circuit consists of IGBT (Insulated Gate Bipolar Translator) power units, and is connected with the generator by a ram side switch; the net side inversion circuit consists of IGBT power units, and is connected with the power grid by an LCL (Lower Control Limit) filter circuit and a net side switch in sequence; and the high-power capacitance type charging circuit is characterized in that a charging resistor is connected at the net side switch in parallel, and the switch-on and switch-off of the charging resistor is controlled by a charging switch which is connected with the charging resistor in series. In the utility model, direct-current bus voltage can reach in a safety capacitance type voltage range in advance before the wind power converter starts to work, and the service life of a capacitor is prolonged, the circuit has simple structure, the cost is low, the charging speed is quick, the charging voltage is high, and the harmonic suppression effect is good.

Description

High-power wind turbine current transformer storage capacitor charging circuit

Technical field

The utility model belongs to wind power plant, relates to a kind of high-power wind turbine current transformer storage capacitor charging circuit.

Background technology

In voltage type PWM heavy-duty rectifier (VSR) main circuit of wind generator system, as shown in Figure 1, DC side comprises the pusherside rectification circuit 01 that is made of the IGBT power cell, the pusher side rectification circuit connectsgenerator 02 through the pusher side switch, AC side then comprises the netside inverter circuit 03 that is made of the IGBT power cell, and net side inverter circuit is connectedelectrical network 05 through LCL filter circuit 04 with net side switch.Usually can adopt storage capacitor 06 to carry out dc energy storage in DC side, storage capacitor both can cushion the power conversion between AC side and DC side load, stablized the VSR dc voltage, also can suppress the DC side harmonic voltage.But in high-power MW level wind electric converter, dc voltage reaches 1000VDC, if when current transformer is started working this step voltage will directly be carried in the storage capacitor two ends, with the grievous injury storage capacitor life-span, especially for the occasion of electrochemical capacitor as storage capacitor.So before the work of high-power MW level current transformer, can carry out precharge to storage capacitor usually, with the protection storage capacitor.

The rated line voltage 690V because direct-drive wind power generation convertor gets access to grid, all can utilize line voltage that electric capacity is charged when usually considering the precharge problem of storage capacitor, existing current transformer storage capacitor precharge scheme is the two-phase line voltage to be carried out rectification electric capacity is charged, as shown in Figure 2.It openscharge circuit 07 earlier before current transformer is started working, storage capacitor is carried out precharge, turn-offs charge circuit then, makes current transformer begin operate as normal, and this charge circuit belongs to the uncontrollable rectification circuit of single-phase bridge.This circuit and method are present MW level current transformer main flow charging methods, and its defective is: 1, the charging interval is long; 2, the harmonic current composition is very big in the charging current, though can not influence the performance of storage capacitor, but can produce additional harmonic loss, reduce the efficient of equipment, and might make voltage, the current sensor at storage capacitor two ends the inaccurate phenomenon of metering occur; 3, because independent rectification module is set, thereby its charge circuit cost is higher.

Summary of the invention

The utility model wants the technical solution problem to be, the high-power wind turbine current transformer storage capacitor charging circuit that a kind of circuit structure is simple, the storage capacitor harmonic current is little, the charging interval is short is provided.

High-power wind turbine current transformer storage capacitor charging circuit of the present utility model includes by the pusher side rectification circuit and the net side inverter circuit that are connected between generator and the electrical network; The pusher side rectification circuit is made of the IGBT power cell, and connects generator through the pusher side switch; Net side inverter circuit is made of the IGBT power cell, and is connected electrical network through the LCL filter circuit with net side switch successively; Be connected with storage capacitor between a pair of connection contact between pusher side rectification circuit power cell and the net side inverter circuit power cell; It is characterized in that at net side switch place charged in parallel resistance, charging resistor is controlled its break-make by the charge switch of series connection with it.

The utility model is not before current transformer is worked, connect charging resistor, utilize in the IGBT power cell that original fly-wheel diode carries out precharge to storage capacitor on the IGBT switching tube brachium pontis, can guarantee that DC bus-bar voltage is before current transformer is started working, reach an electric capacity safe voltage scope in advance, prolong electric capacity useful life; Not only circuit structure is simple for it, cost is low, and charging rate is fast, charging voltage is high, harmonic suppression effect is good.

Description of drawings

Fig. 1 is existing wind electric converter circuit theory diagrams;

Fig. 2 is existing wind electric converter storage capacitor charging circuit schematic diagram;

Fig. 3 is a wind electric converter storage capacitor charging circuit schematic diagram of the present utility model.

Embodiment

As shown in Figure 3, wind electric converter storage capacitor charging circuit of the present invention has identical with the traditional wind electric converter system pusherside rectification circuit 11 that is made of the IGBT power cell and netside inverter circuit 13, pusher side switch (not providing among the figure), LCL filter circuit 14,net side switch 18,storage capacitor 16, in addition, net side switch place charged inparallel resistance 19, charging resistor is by charge switch 17 its break-makes of control of series connection with it.

In the utility model course of work, before current transformer is not worked, be that pusher side switch and net side switch are when all disconnecting, connect charging resistor, pass through line voltage, utilize in the IGBT power cell that original fly-wheel diode carries out precharge to storage capacitor on the IGBT switching tube brachium pontis, make DC bus-bar voltage before current transformer is started working, reach an electric capacity safe voltage scope in advance, and then turn off charge switch, startup current transformer.

Claims (1)

1. high-power wind turbine current transformer storage capacitor charging circuit includes by the pusher side rectification circuit and the net side inverter circuit that are connected between generator and the electrical network; The pusher side rectification circuit is made of the IGBT power cell, and connects generator through the pusher side switch; Net side inverter circuit is made of the IGBT power cell, and is connected electrical network through the LCL filter circuit with net side switch successively; Be connected with storage capacitor between a pair of connection contact between pusher side rectification circuit power cell and the net side inverter circuit power cell, it is characterized in that: at net side switch place charged in parallel resistance, charging resistor is controlled its break-make by the charge switch of series connection with it.

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