CN104600739A

CN104600739A - Variable-speed wind turbine

Info

Publication number: CN104600739A
Application number: CN201310532142.8A
Authority: CN
Inventors: 不公告发明人
Original assignee: XINCHANG COUNTY GUANYANG TECHNOLOGY DEVELOPMENT Co Ltd
Current assignee: XINCHANG COUNTY GUANYANG TECHNOLOGY DEVELOPMENT Co Ltd
Priority date: 2013-11-03
Filing date: 2013-11-03
Publication date: 2015-05-06

Abstract

The invention provides a variable-speed wind turbine and discloses a variable-speed wind driven generator which is controlled by use of standard powder and controlled by depending on intervals. The variable-speed wind turbine may comprise a generator; power is provided by a power network and a power conversion system coupled to the generator. The power conversion system may comprise at least one passive power grid side rectifier. The power conversion system may comprise a passive power grid side rectifier capable of providing power supply and used by the generator. The variable-speed wind turbine also can be controlled by use of the standard power to provide more accurate control on the electrical quantity of the power grid. The variable-speed wind turbine can be further controlled by depending on a variable pitch; as a result, the response of the wind turbine can be improved.

Description

Variable speed wind turbines

Technical field

The present invention relates to mechanical field, particularly relate to a kind of variable speed wind turbines, and more specifically, the variable speed wind turbines of pitch control that the power with passive electrical net-side rectifier and scalar controls and relies on.

background of invention

Wind turbine is a kind of energy conversion device.It converts the practical electrical network that kinetic energy wind energy transformation is electric energy to.Such power conversion is usually directed to the wind blade of the rotor of the generator rotated by wind energy.Specifically, the air blade of wind creates one in epitrochanterian power, makes rotor rotating machinery Wind resource change become electric energy.Therefore, the function of the power of the wind of the electrical power of such generator.Because fluctuations in wind speed, the power being applied to rotor can be different, but, need the electrical power a constant frequency, such as 60 hertz or 50 hertz.Therefore, wind turbine must provide electric power at constant Frequency Synchronization to electrical network.

The wind turbine providing the electrical power of constant frequency of one type, wind turbine is a fixed speed.The generator shaft that such turbine needs, rotates with constant speed.Generator shaft, with the shortcoming that constant speed rotates is, it does not utilize the power of the wind when running at high speed, and must be prohibited at low wind speed.That is, a generator is by rotating with constant speed, limits its energy conversion efficiency.Therefore, in order to obtain best power conversion, the wind speed of the alternator speed of rotation is directly proportional.

The wind speed that the rotating speed of the rotary generator of the wind turbine maintenance of one type is proportional is variable-ratio wind turbine.Specifically, such turbine, makes a generator, and the speed of continuous variable rotates, to adapt to the wind speed fluctuated.By changing the alternator speed rotated, power conversion, in one widely wind speed range, can be optimized.Variable speed wind turbines before this, but, need complicated and expensive circuit perform power transfer and control turbine.

From electrical network electric power is provided to rotor windings by rear end to rotary furnace, grid side converter is as a rectifier, and the AC signal of constant frequency converts direct voltage to, and this is placed on DC link.Generator side transducer converts the generator of the AC signal of variable frequency to as the direct voltage on the DC bus of an inverter, thus on stator, to keep constant high frequency power.So that electric power is provided to electrical network by rear end to rotary furnace, convert direct voltage from the generator-side converter of rotor windings to as the AC signal of rectifier and variable frequency, this is placed on DC link.Then, the DC that grid side converter is converted to the power of the fixed frequency of electrical network as the direct voltage of an inverter is linked to.Rear end to a shortcoming of such transducer is, it needs complicated and expensive circuit, utilizes the active switch of two transducers.As previously mentioned, usually can use in active Switching Power Supply transfer process and cause unnecessary power loss and unnecessary high order harmonic component to electrical network.In addition, as in existing filling power converter, two transducers must be controlled, than passive component, active element is insecure.

The control of the generator-side converter of one type, relates to and AC signal is converted to Parametric Representation threephase generator electric parameters and coordinate transform, makes generator can control to use DC value.Such control is " a kind of form of Field orientable control (FOC).The shortcoming adopting FOC type to control, in the transition process of useful information interchange signal, may be lost.Specifically, the AC signal of the three phases of FOC supposition is symmetrical.In some cases, AC signal is asymmetric, converts D. C. value to transfer process from AC signal, and AC information can be used to lose.

In addition, because when FOC is converted into DC value, meeting drop-out, FOC can not be used in a system, separately controls the electric parameters (such as, voltage, electric current) of the electrical network of each phase.Theoretically, this should not form a problem, because the desirable power grid electric in each stage should be not different.But, in practice, in each stage, may change to the electric parameters of electrical network, cause the generating of the developmental generator of uneven thermal stress and non-optimal.Therefore, this by be desirable electrical network three phases in each control these electric parameters independently.

The pitch controller of the wind turbine of another aspect.The speed that typical generator rises to preselected constant is run, and is called as " rated speed." work as generator, or arrive before, when rated speed is run, turbine controls the restriction of the blade angle of turbine, in the face of wind, is called as " propeller pitch angle of blade ".By controlling propeller pitch angle, turbine can maintain generator in rated speed.Pitch controller, but operation is compared at low frequencies usually, power conversion controller.Therefore, the fast-changing speed of tone controller delay of response, this is typical caused by fitful wind.

Summary of the invention

One aspect of the present invention discloses a kind of variable speed wind turbines.Such as, variable-ratio turbine can comprise power electric generators, with power network and the power conversion system being coupled to generator.Power conversion system can comprise the generator of at least one passive grid side rectifier power source.Another aspect of the present invention, discloses a variable-ratio wind turbine, the power of scalar can be used to control, to the electric parameters of electrical network, control more accurately to provide.Another aspect of the present invention, discloses a kind of variable speed wind turbines, can use dependence, improves the pitch control of the wind turbine of response speed.

specific implementation method

Variable speed wind turbines as herein described provides a power supply changeover device simplified, and uses passive electrical net-side rectifier, thus avoids use active switch.Such as, can by passive rectifier diode.Therefore, passive grid side rectification does not require the control of processor, provides a more reliable power supply changeover device.Particularly, the more reliable specific activity component of passive component.In addition, because the power loss caused in active switch Power convert process, the passive electrical net-side rectifier that can improve is for the power conversion efficiency of wind turbine.In addition, use passive grid side rectification not produce high order harmonic component, and provide more expensive and more not complicated circuit, for the power converter at described wind turbine.

This wind turbine additionally provides the Instantaneous Control controlling to be provided to the generator rotor current of the instantaneous power of power network.The power of scalar controls, and can be in response to the electrical characteristic of the reality of the electrical network into each stage.

Wind turbine also uses the change oar of dependence to control, the dependence on power-supply controller of electric.Particularly, an execution mode discloses a kind of change oar controller of low speed from high-speed power controller, its Received signal strength or information, thus improves response speed, becomes oar controller.

As being discussed in further detail below, variable speed wind turbines can be implemented double-fed wound rotor induction generator and produce electric energy.This generator can be operated in lower than synchronizing speed higher than synchronous speed.

Synchronous speed is the speed of the rotor (speed) of machinery, rotates with identical speed at stator field.In the context of wind turbine hereinafter described, synchronizing speed can be 1800 turns per minute.Under normal circumstances, stator frequency is fixed as mains frequency.As described herein to realize, by the active element of the rotor-side converter or inverter that control a generator, and the power of constant frequency by the spacing that controls turbine blade, required amount can be provided the stator winding from generator.Exciting power lower than synchronizing speed, can use passive grid side rectification to be supplied to the rotor of generator from electrical network at spinner velocity.At the spinner velocity higher than synchronous speed, poower flow can be reversed, and because unnecessary electric power is from the rotor of generator, this needs unnecessary power consumption at power converter.

Passive grid side rectifier configurations

The circuit of an execution mode of the variable speed wind turbines 100 that the present invention is consistent.Wind turbine comprises a generator to be had stators and rotators and is connected to generator rotor shaft.Although not shown, generator rotor shaft connects the wind turbine of air blade.One realizes this connection can be by a gear box.In one embodiment, generator is implemented as double-fed wound rotor induction generator, and rotor and stator all comprise two poles, and the rotation of the armature spindle of phase winding generates electricity.The AC signal of the fixed frequency that generator provides is from stator to power network.Rotor can receive from the operation of power conversion system slippage and exciting power generator by passive electrical net-side rectifier.The unnecessary power converter that rotor also can directly produce, it can consume unnecessary generating.

Generator is coupled to power converter by inductor.Inductor as a filter, to prevent the change in voltage imperial palace generator on winding.Power converter is coupled to power transformer.Power transformer can be, such as, and 690V/480V power transformer and an integrated reactor or the choke induction be separated.Particularly, power transformer supply electrical network 690V and 480V power supply changeover device.Power transformer is coupled to the charging circuit of electrical network, comprises switch and resistor, and power converter charges, and the surge current do not shown, passes through power transformer.The Electromagnetic Compatibility filter that this circuit is also coupled, the harmonic distortion of the power converter that filter causes.One overvoltage protection (OVP) circuit is also coupled to generator.OVP circuit working is not damaged under overpressure condition, with protection power source transducer.

Generator power supply by stator to electrical network.Stator is connected to electrical network by delta (" delta ") connector and main connector or by Y type connector and main connector.Can stator winding be configured with main connector A connector, make them at triangle joint.Breeches joint and main connector can configure, so they connect winding at stator at a Y.In one implementation, identical stator winding DELTA with Y is used to be connected.By this way, Y connection can reduce and allows in wider velocity interval in the iron loss of stator and low wind speed.Therefore, generator optionally can provide electric power from stator by DELTA electrical network.Connector and main connector or connector and main CONNECTER.In addition, this makes wind turbine, to reduce power loss, is connected to the Delta DELTA of electrical network by generator selectively.Connector 131A and main connector or Y type connector 131B and main connector 105.Grid work a fixing frequency as 3 phase 690V utility networks.This grid also can be operated in other voltage or fixing frequency, such as 50 hertz, or has the different numbers of phases.

Power supply changeover device

Variable speed wind turbines comprises and is coupled to power converter to control the assembly in turbine, comprises the power output stream and control assembly that regulate turbine, as the transducer processor of power supply changeover device.In one embodiment, transducer processor controls the active element in power converter, so that control is supplied to total electricity of electrical network.Such electricity may comprise the total current and power that are supplied to electrical network.The operation that transducer processor controls power converter will be described below in more detail.

Power supply changeover device comprises an active generator side inverter, DC bus, power consumption element, and passive grid side rectifier.For illustrative purposes, shown in power supply changeover device and single element, but the element of any amount, can be implemented at power converter.Such as, power converter can comprise the passive rectifier parallel passive rectifier of any amount.When such structure is useful especially wind turbine, provide a low-power mode and at least one higher power mode, wherein one or more parallel rectifiers, start in higher generator mode (secondary).Multiple heat-sinking capability element also can be set.

Wind turbine normally operate in below synchronizing speed, poower flow is directed into generator from power converter.Therefore, in most of the cases, the direct voltage on the DC bus changed as inverter of the assembly of effective inverter is converted to the AC signal generator of variable frequency.Therefore, in the following embodiments, active inverter referred to as " inverter ".But in some cases, wind turbine can be operated in higher than synchronous speed, poower flow is made to be can be used as a rectifier with assembly that is active-inverter on the contrary.That is, when poower flow is contrary, the work of active-inverter is produced from generator to be used for power converter and to be converted to the unnecessary electric power of the conversion of direct voltage.Like this, the heat dissipation element that unnecessary power can consume or discharge, this will be further explained in detail below.

Active-inverter comprises active element or the switch of a three-phase bridge configuration.In one embodiment, the IGBT of active switch.These active switchs can be the switches of other type, such as, such as, and bipolar junction transistor or field-effect transistor.

In one embodiment, pulse width modulation (PWM) current regulation technique is according to a scalar control algolithm (" scalar control algolithm "), as mentioned below, for optionally controlling the active switch in active-inverter.Scalar control algolithm allows each stage in each stage in the grid of the electric parameters measured from individual and/or that independently PWM controls rotor basis.Scalar control algolithm can control, the electric parameters in each stage separately and/or independently in grid.Although other control method also can be adopted, as used in the direct torque of Field orientable control, as described in the patent of ' 187, FOC type controls to implement in a different manner, perform different functions, and achieve poor result than Poewr control method described herein.

Will now describe lower than the operation with the active inverter higher than synchronous speed.Below synchronizing speed, the AC signal that the direct voltage on DC bus converts variable frequency to, as an inverter, is provided to generator by active inverter.Higher than synchronous speed, active inverter is used as rectifier, and the AC signal of variable frequency is converted to DC voltage, and DC bus is positioned in from generator.As being described in further detail below, when the direct voltage on DC bus exceedes threshold value, the voltage on DC bus reduces by power dissipation component, and what produce from generator burns unnecessary electric power.

Link comprises a series of capacitor element.In some embodiments, the resistance that can add one or more groups is to the element of discharging capacitors and improve symmetry.Particularly, the voltage drop of the both link ends of each several part should be substantially identical (or almost symmetry).But DC bus, realizes in can configuring with the memory circuit of the voltage of other types.

Claims

1. variable speed wind turbines, comprise: device, to there is provided the Blast Furnace Top Gas Recovery Turbine Unit (TRT) of electric power with lower than synchronous speed with dissipate from the superfluous synchronizing speed of the generating capacity of above-mentioned Blast Furnace Top Gas Recovery Turbine Unit (TRT) to the power conversion system of power network from electrical network for generation of electric power, with the power conversion system that the controller being coupled to described electric power coversion system controls, the control device of power supply is provided, for generating, variable speed wind turbines, comprise: direct current (DC) link couples of a generator-side converter is to the power dissipation element of generator-side converter, it consumes unnecessary electric power from generator with being connected to DC link selection, fix with a passive electrical net-side rectifier conversion and be converted to direct voltage from alternating current (AC) signal of the frequency of electrical network, wherein, generator-side converter is provided to by the direct voltage of DC bus and generator-side converter the AC signal that generator is converted to variable frequency and converts direct voltage to.

2. variable speed wind turbines, is characterized in that, comprising: receive the poower flow of self generator, determine, if generator operation is below or above synchronous speed; Indicate the generator of the poower flow received, if be confirmed as being operated in lower than the unnecessary electric power of synchronizing speed generator and dispel the heat from the poower flow received, if be determined to be in more than synchronous speed to run generator.

3. method according to claim 3, is characterized in that, the power that described instruction receives, and comprising: d. c. voltage signal converts the AC signal of variable frequency to, and is directed to the AC signal of generator.

4. method according to claim 3, is characterized in that, the electric power that described consumption is unnecessary, and the AC signal comprising variable frequency is converted to d. c. voltage signal, and the generator of difference of d. c. voltage signal from generator commander.

5. method as claimed in claim 5, is characterized in that, comprises the d. c. voltage signal consuming the superfluous power supply of unnecessary power consumption and produce.

6. variable speed wind turbines, it is characterized in that, comprise: one is connected to air blade, for generation of the generator of electrical power, and be coupled to the power converter of generator, with the electric power controlling to produce, power supply changeover device comprises the DC link of a generator-side converter, a power dissipation component, with a passive electrical net-side rectifier, it is characterized in that, the AC signal that the AC signal that described master end generator converts variable frequency to is provided to generator or variable frequency is converted to the generator of direct voltage, the signal of DC link is supplied to from the d. c. voltage signal of DC bus, it is characterized in that, described power dissipation component consumes the signal that unnecessary electric power is produced by the direct voltage of generator-side converter.

7. method according to claim 7, is characterized in that, described generator-side converter, and the AC signal being converted to variable frequency from DC bus converts d. c. voltage signal to, if generator operation is at the variable speed wind turbines lower than synchronizing speed.