SU1078574A1 - Method of adjusting asynchronous rectifier windwheel generator - Google Patents

Abstract

1. METHOD FOR CONTROLLING AN ASYNCHRONOUS VENTILATION WITH A WIND GENERATOR With a frequency converter in the stator circuit, at which an adjustable parameter is measured, it is compared with the compressed value and form the frequency control signal of the valves of the specified frequency converter, which is equal to the iTO, with the aim of reducing the installed power and reducing the weight and size dimensions of the induction machine, control the frequency control signal of the valve of the frequency converter, from It sets the generator magnetic circuit with a setpoint determined by saturation, and when the monitored signal reaches a value greater than the setpoint, the phases of the stator winding are switched from the triangle connection circuit to the connecting circuit: star, and when the monitored signal drops to , less (O Neck settings, switch the phases of the winding; ki stator of the asynchronous generator; from the star connection scheme to the triangle connection scheme I. M 00 CL 41

Description

2, a method according to claim 1, characterized in that the voltage at the output of the asynchronous valve wind generator is measured and the setpoint is changed in proportion to the measured voltage.

The invention relates to the generation and conversion of electric power, in particular, to methods of controlling asynchronous generators operating in wind turbines.

Methods are known for controlling asynchronous generators with valve converters in a stator circuit, the voltage of which is stabilized by adjusting the stator current frequency as a function of the output voltage deviation from the set one. With this control, the control signal is the signal that is fed to the input of the master oscillator of the adjustable frequency converter ij.

The disadvantage of such control of an asynchronous generator operating in a wind turbine, where the generator power is commensurate, with the power of a wind turbine, is a sharp decrease in the frequency of rotation of the drive shaft with increasing electrical load of the generator above the maximum power developed by the wind drive. This leads to the exit of the wind power installation from the operating mode.

Closest to the present invention is a method of controlling an asynchronous valve generator, according to which the stator current frequency is controlled by influencing the control sigal of the master generator of a variable frequency gate converter in the stator circuit of the asynchronous mash as a function of the maximum power developed by the wind drive. In this case, to determine the electrical power, the output voltage of the generator 2 is measured.

The known method allows to expand the range of working frequencies of rotation of the wind-drive shaft down from the nominal, however, with a significant expansion of the range of rotational frequencies, it is necessary to increase the mass and guarity of the asynchronous machine, since its nominal frequency of rotation must be chosen close to the nominal operating frequency of the wind-drive, to prevent a sharp increase magnetizing current due to saturation and magnetic circuit. To ensure sufficient overload capacity at the maximum operating frequency of rotation of the shaft,

increase the nominal installed capacity of the asynchronous machine. The purpose of the invention is to reduce the installed capacity of an asynchronous machine and reduce its weight and size parameters.

This goal is achieved by the fact that according to the method of controlling an asynchronous valve wind generator

Q with a frequency converter in a stator circuit, at which an adjustable parameter is measured, compare it with a set value and generate a frequency control signal

 switch valve specified

frequency converter, control the valve switching frequency control signal of the specified frequency converter, compare it with the setpoint determined by saturation

0 magnetic generator circuit, and when the monitored signal reaches a value greater than the setpoint, the stator winding phases are switched from the triangle connection circuit to the star connection circuit, and when the monitored signal drops to a smaller value, the asynchronous generator of the star connection circuit is switched scheme

0 compare triangle.

Moreover, the voltage at the output of the asynchronous valve wind generator is measured and the setpoint I is changed in proportion to the measured voltage.

On . 1 shows a block diagram of a device implementing the proposed method; in fig. 2 - the same, option 1a fig. 3 is a diagram, which shows the operation of an asynchronous valve generator.

The device includes a drive wind turbine 1, which causes the rotation of the shaft of the asynchronous machine; asynchronous machine 2, which is a generator of electricity; a power switch 3 that serves to turn on the AM winding according to a star or delta circuit (it can be made on contact or non-contact

0 controlled keys); adjustable frequency semiconductor (valve) converter 4, which performs the function of adjusting the stator current frequency of the asynchronous machine;

5 battery 5 of generator 6 setups, which converts the input voltage (Ueiir) of the frequency switch of PRP valves, AM power regulator 7 (URM), which regulates the stator current frequency of the asynchronous machine 2 as a function of the maximum power of the wind drive; voltage sensor 8, with which the setpoint voltage is obtained, is proportional to the output voltage of the wind generator comparison device 9, switching device 10 that generates the control signal of the power switch (can be performed, for example, in the form of a polarized relay or on the basis of an operational amplifier). FIG. 3 denotes: it is the phase current of the stator asynchronous g busbars in relative units; i) and the current of the stator in relative units; CjJ, is the frequency of the stator current, at which the stator winding of the asynchronous machine is switched from the delta connection circuit to the star connection circuit when the output voltage is G (i) i equal to the rated voltage (Icode); Op.2 stator current frequency at which the specified switching occurs with Up A, the I f (co) curves when the stator winding of the asynchronous machine is triangular, and Y is the Ij-f (and) curves when the stator winding of the asynchronous machine is turned into a star. The control of the asynchronous valve wind generator is as follows. With a nominal voltage, the generator output decreases the maximum power of the wind drive and decreases the frequency of the stator current and the slip of the asynchronous machine 2, so that the motor generated by the generator does not exceed the maximum power of the wind drive. The active current of the stator of the generator 2 decreases, which initially (at frequencies slightly lower than the nominal, leads to a decrease in the phase current of the stator (Fig. 3). If the frequency decreases further, the stator current increases sharply due to saturation of the magnetic circuit of the machine. At point 11 (FIG. 3) The input voltage of the generator 6 exceeding the voltage supplied, for example, from voltage sensor 8 (FIG. 2), and the output signal of the comparator device 9 will change sign, this will cause the switching device 10 to give a signal switch 3 to turn on the stator winding of the asynchronous machine 2 into a star. The phase of the stator will correspond to point 12 (Fig. 2) and with a further decrease in frequency will vary along a curve indicated by a solid line. In the case of an asynchronous wind generator at reduced (relative to nominal) voltage In this case, for example, in the case of an insufficiently charged rechargeable battery 5, the dependence of the stator current on frequency changes somewhat. As can be seen from FIG. 3, the increase in the stator current of the asynchronous machine due to the saturation of the magnetic circuit in this mode occurs with a decrease in the frequency of the current, since the flow value is determined by the ratio Uj / and ,. Switching the stator winding of an asynchronous machine from a triangle to a -star-type 0.9-etsd will occur (Fig. 3), also at a lower frequency, since the polarity of the signal at the output of the reference device 9 will be observed npHtJ (-0.9-w Thus, the switching of the winding of the asynchronous machine 43 of the square to the star occurs at approximately the same saturation of the magnetic circuit of the asynchronous machine, as with the proposed method of controlling the ratio Ur / W at the time of switching is constant. The triangles in a triangle can be produced at frequencies somewhat higher than the pitch, i.e., at the moment when the input voltage of the master oscillator 6 exceeds the voltage .1, which is proportional to the output voltage of the generator, by 3-5%; in this case, the stator phase current Thus, the proposed method of controlling an asynchronous valve wind generator allows, without overloading the asynchronous current, to reduce the stator current frequency of the asynchronous machine and, accordingly, the operating frequency of the wind drive shaft These factors are approximately twice as small as nominal, and allow the nominal power of the asynchronous machine to be close to the nominal power of the wind drive, and the nominal speed of the asynchronous machine to close to the nominal frequency of rotation of the wind drive shaft. This makes it possible to reduce the mass-scale parameters and the established value of the asynchronous machine, which leads to the suffocation of the entire wind turbine as a whole and the economy of the material.

Claims (2)

1. METHOD FOR CONTROLLING AN ASYNCHRONOUS VENTAL WIND GENERATOR with a valve frequency converter in the stator circuit, in which the adjustable parameter is measured, compare it with a predetermined value and form a frequency control signal переключения switching valves of the specified frequency converter, which is different, in order to: reduce the installed power to reduce the overall dimensions of the asynchronous machine, control the control signal of the switching frequency of the valves of the inverter frequency converter, compare it 'With the set point' is determined by saturation. the generator’s magnetic circuit, and when the controlled signal reaches a value higher than the setpoint, the phases of the stator winding are switched from the delta connection circuit to the star connection circuit, and when the controlled signal decreases to a value less than the lower setting, the winding phases are switched! the stator of the asynchronous generator from the star connection circuit to the triangle connection circuit ^. Z. J, 4 SU-.I. 1078574 2. The method according to π. 1, characterized in that the voltage at the output of the asynchronous valve wind generator is measured and the setting is changed in proportion to the measured voltage. ί