JP2014054036A - Wind force power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wind force power generation device which reduces standby power in a control power supply and the like, reduces switching loss in an active element in a power converter, and downsizes the device.SOLUTION: A wind force power generation device comprising a power generator converter which is not a converter composed of an active element but a converter composed of a diode that is a passive element, and a system inverter for controlling a power generator controls power output by the system inverter on the basis of the number of rotations of the power generator. Thereby, downsizing of the device, reduction in standby power, and reduction in switching loss can be implemented.

Description

  The present invention relates to a wind power generation system that generates power using wind power, and relates to a wind power generation apparatus that efficiently generates power for wind power.

  In the wind power generation system, in order to efficiently distribute the energy obtained from the windmill to the commercial system, the generator output is once converted to direct current by the converter, and the converted direct current is converted to alternating current by the inverter and distributed to the commercial system. (For example, see Patent Document 1)

  FIG. 4 is an example of a main circuit configuration diagram of a conventional wind power generation system.

  In FIG. 4, 1 is a windmill, 2 is a generator, 51 is a converter, 4 is a filter capacitor, 5 is a system inverter, 6 is an AC reactor, 7 is an AC capacitor, 8 is a commercial system open contactor, and 9 is a commercial system. is there.

  The converter 51 includes switching elements 52 to 57 and free wheel diodes 58 to 63 connected in reverse parallel to the respective switching elements 52 to 57. Switching elements 52 and 53 are connected in series to form an R-phase arm of converter 51, switching elements 54 and 55 are connected in series to form an S-phase arm of converter 51, and switching elements 56 and 57 are connected in series to form converter 51. A T-phase arm is configured, and the filter capacitor 4 is connected to the output of the converter 51. The generator 2 connected to the input of the converter circuit 51 is controlled by turning on and off the switching elements 52 to 57 so that the phases of each phase are shifted by 120 degrees from each other.

  The system inverter 5 includes a filter capacitor 4 on the input side, and includes switching elements 27 to 32 and free wheel diodes 33 to 38 connected in reverse parallel to the switching elements 27 to 32. Switching elements 27 and 28 are connected in series to form a U-phase arm of system inverter 5, switching elements 29 and 30 are connected in series to form a V-phase arm of system inverter 5, and switching elements 31 and 32 are connected in series. A W-phase arm of the inverter 5 is configured. By switching on and off the switching elements 27 to 32 so that the phases of each phase are shifted from each other by 120 degrees, alternating current is output to the commercial system connected to the output side of the system inverter 5.

  The AC reactor 6 and the AC capacitor 7 constitute an AC filter, and convert the rectangular wave voltage output from the system inverter 5 into a sine wave.

  The commercial system open contactor 8 opens and releases the commercial system that is trying to link the AC output through the AC reactor 6.

  In many cases, the converter circuit 51 is controlled by the number of revolutions or torque in the control of the generator 2.

  In some cases, active power is used to control the generator 2. (For example, refer to Patent Document 2).

  The system inverter 5 uses the DC output of the converter 51 as a power source and converts it into an AC output that is voltage / frequency and phase controlled for a commercial system.

Japanese Patent No. 3435474 JP 2011-217574 A

  However, in the prior art, two active power converters are required: a converter for generator control and a system inverter for system side control.

  In addition, as the number of active power conversion devices increases, standby power of the control power supply increases and switching loss of active elements of the power conversion device increases, which increases the cooling mechanism and makes it difficult to reduce the size of the device. Become.

  Therefore, in the present invention, the converter for the generator is not a converter using an active element but a converter using a diode of a passive element, and the generator is controlled by a system inverter so that the apparatus can be downsized and standby power can be reduced. The purpose is to reduce.

  The present invention comprises a generator driven by a windmill, a rectifier that converts an alternating current output of the generator into direct current, a filter capacitor connected to the output of the rectifier, and a plurality of switching elements constituting a circuit of a plurality of phases. A system inverter connected to the output of the rectifier, an AC reactor and an AC capacitor for converting a rectangular wave voltage output from the system inverter into a sine wave, and an output of the AC reactor to connect to a commercial system A commercial open contactor that performs release, a rotation sensor that detects the rotational speed of the generator, a first voltage sensor that detects a voltage applied to the filter capacitor, and a voltage on the output side of the AC reactor. A second voltage sensor for detecting, a current sensor for detecting a current output to the commercial system, a third voltage sensor for detecting a voltage of the commercial system, and the rotation sensor. Means for calculating an output power command based on the number of rotations detected by the sensor, means for calculating an effective value of the output voltage based on the voltage detected by the second voltage sensor for detecting the voltage on the output side of the AC reactor, Means for calculating an output current command based on the output power command and an output voltage effective value; means for calculating a voltage phase based on a voltage detected by the third voltage sensor for detecting a voltage of a commercial system; and the output current The three-phase voltage command for calculating the three-phase voltage command output from the system inverter based on the command, the voltage phase, and the output current, and a plurality of switchings constituting the inverter based on the voltage and the carrier signal applied to the filter capacitor In a wind turbine generator having means for generating a gate signal to the element, the power output from the system inverter based on the number of revolutions of the generator It is characterized by controlling.

  As a result, the inverter for the system can also serve as a generator control without using a converter for controlling the generator, and the standby power can be reduced by downsizing the entire wind power generator and reducing active elements. it can.

  Further, the power factor of the output to the commercial system is not fixed and may be an arbitrary variable power factor.

  Further, the control of the power output from the inverter based on the number of revolutions of the generator is not a fixed value, but may be maximum power point tracking control (MPPT control; Maximum Power Point Tracker control).

  According to the present invention, in the wind turbine generator having the above-described inverter, it is possible to reduce the standby power by reducing the size of the entire wind turbine generator and reducing the number of active elements.

It is a figure which shows the circuit of the wind power generator which concerns on this invention. Example 1 It is a figure which shows an example of the control block structure which concerns on this invention. Example 1 It is a figure which shows an example of the control block structure which concerns on this invention. Example 1 It is a figure which shows the circuit of the wind power generator by a prior art. It is a figure which shows an example of the control block structure which concerns on this invention. (Example 2) It is a figure which shows an example of the control block structure which concerns on this invention. (Example 2) It is a figure which shows an example of the control block structure which concerns on this invention. (Example 3)

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a diagram illustrating a wind turbine generator according to a first embodiment of the present invention, FIG. 2 is a diagram illustrating an example of a control block configuration according to the first embodiment of the present invention, and FIG. 3 is a control according to the first embodiment of the present invention. It is a figure which shows an example of a block structure.

  In FIG. 1, a wind turbine generator includes a windmill 1, a generator 2, a rectifier 3, a filter capacitor 4, a system inverter 5, an AC reactor 6, an AC capacitor 7, a commercial system open contactor 8, A rotation sensor 11, voltage sensors 12 to 15 and 18 to 19, current sensors 16 and 17, and a control unit 71 are provided.

  The rectifier 3 includes diodes 21 to 26. Diodes 21 and 22 are connected in series to form an R-phase arm of rectifier 3, diodes 23 and 24 are connected in series to form an S-phase arm of rectifier 3, and diodes 25 and 26 are connected in series to form a T-phase arm of rectifier 3. Is configured. As a result, the AC power generation output of the generator 2 is converted to DC.

  The filter capacitor 4 smoothes the direct current converted by the rectifier 3.

  The system inverter 5 includes switching elements 27 to 32 and free wheel diodes 33 to 38 connected in reverse parallel to the switching elements 27 to 32. Switching elements 27 and 28 are connected in series to form a U-phase arm of inverter 5, switching elements 29 and 30 are connected in series to form a V-phase arm of inverter 5, switching elements 31 and 32 are connected in series, and A W-phase arm is configured. By switching on and off the switching elements 27 to 32 so that the phases of each phase are shifted from each other by 120 degrees, alternating current is output to the commercial system connected to the output side of the system inverter 5.

  The AC reactor 6 and the AC capacitor 7 constitute an AC filter, and convert the rectangular wave voltage output from the system inverter 5 into a sine wave.

  The commercial system open contactor 8 opens and releases the commercial system that links the AC output through the AC reactor 6.

  The rotation sensor 11 detects the rotation speed Ng of the generator 2.

  The voltage sensor 12 detects the voltage Vc applied to the filter capacitor 4.

  Voltage sensors 13 to 15 detect three-phase output voltages Vu, Vv, and Vw that are applied to the output side of AC reactor 6.

  Current sensors 16 and 17 detect three-phase output currents Iu and Iw that are output to a commercial system.

  The voltage sensors 18 and 19 detect the system voltages VLu and VLv of the commercial system.

  The control unit 71 inputs values from the rotation sensor 11, voltage sensors 12 to 15, current sensors 16 and 17, and voltage sensors 18 and 19, and gate signals Gup, Gun, Gvp, Gvn to the switching elements of the system inverter 5. , Gwp, Gwn are output.

  FIG. 2 shows the configuration of the control unit 71. The control unit 71 includes an output power command calculation unit 72A, an output voltage effective value calculation unit 73, a divider 74, a system voltage phase calculation unit 75, and 3 Phase voltage command calculation unit 76A and gate signal generation unit 77 are provided.

  The output power command calculation unit 72A calculates the output power command Pout * output from the system inverter 5 to the commercial system based on the generator rotational speed Ng.

  The output voltage effective value calculation unit 73 calculates the output voltage effective value Vout based on the three-phase output voltages Vu, Vv, and Vw.

  Divider 74 divides output power command Pout * by output voltage effective value Vout to calculate output current command Iout *.

The system voltage phase calculation unit 75 performs a PLL operation (Phase based on the system voltages VLu and VLv).
Locked Loop (phase synchronization calculation) is performed to calculate the phase θ of the system voltage.

  The three-phase voltage command calculation unit 76A calculates the three-phase voltage commands Vu *, Vv *, and Vw * based on the three-phase output currents Iu and Iw, the system voltage phase θ, and the output current command Iout *.

  The gate signal generation unit 77 generates a gate signal based on the three-phase voltage commands Vu *, Vv *, Vw *, the carrier signal, and the voltage Vc. For example, a triangular wave comparison method is used in which the carrier signal is a triangular wave and the voltage command is compared with the carrier signal. This gate signal turns on and off the switching element of the system inverter 5.

  FIG. 3 shows the configuration of the three-phase voltage command calculation unit 76A. The three-phase voltage command calculation unit 76A includes a three-phase-dq coordinate conversion unit 81, a current command generation unit 82A, subtraction units 83 and 84, , PI control units 85 and 86, and a dq coordinate-3 phase conversion unit 87.

  The three-phase-dq coordinate conversion unit 81 converts the currents Id and Iq with respect to the dq coordinates based on the three-phase output currents Iu and Iw and the system voltage phase θ.

  Based on the output current command Iout *, the current command generation unit 82A converts current commands Id * and Iq * for the dq coordinates.

  The subtracter 83 subtracts the current Id from the current command Id * and outputs ΔId.

  The subtracter 84 subtracts the current Iq from the current command Iq * and outputs ΔIq.

  The PI control unit 85 performs a PI calculation based on ΔId and outputs a voltage command Vd *.

  The PI control unit 86 performs a PI calculation based on ΔIq and outputs a voltage command Vq *.

  The dq coordinate / three-phase conversion unit 87 converts the three-phase voltage commands Vu *, Vv *, and Vw * for the three-phase coordinates based on the voltage commands Vd * and Vq * and the system voltage phase θ.

  FIG. 5 is a diagram illustrating a wind turbine generator according to the second embodiment of the present invention, and FIG. 6 is a diagram illustrating an example of a control block configuration according to the second embodiment of the present invention. In this embodiment, the power factor command φ from the outside is further input to the output power command calculation unit 76A in Example 1, and 72A, 73 to 75, 77, 81, 83 to 87 are shown in FIGS. Same as 3. By making the power factor variable rather than fixed, it is possible to prevent a voltage rise on the commercial system side.

  The three-phase voltage command calculation unit 76B is based on the three-phase voltage commands Vu *, Vv *, Vw * based on the three-phase output currents Iu, Iw, the system voltage phase θ, the output current command Iout *, and the power factor command φ. Is calculated.

  Based on the output current command Iout * and the power factor command φ, the current command generation unit 82B converts the current command generation unit 82B into current commands Id * and Iq * for the dq coordinates.

  FIG. 7 is a diagram illustrating a wind turbine generator according to Embodiment 3 of the present invention. In this embodiment, the output power command calculation unit 72A according to the first embodiment uses a maximum power point tracking control method instead of a constant function with respect to the rotation speed Ng. 73 to 77 other than the maximum power point tracking control type output power command calculation unit 72B are the same as those in FIG. Thereby, electric power can be taken out from the windmill more efficiently.

  The output power command calculation unit 72B calculates the output power command Pout * output from the system inverter 5 to the commercial system using the maximum power point tracking control method based on the generator rotational speed Ng.

  The present invention can reduce the size of an apparatus and reduce standby power in a wind power generation system that generates power using wind power.

DESCRIPTION OF SYMBOLS 1 Windmill 2 Generator 3 Rectifier 4 Filter capacitor 5 System inverter 6 AC reactor 7 AC capacitor 8 Commercial system open contactor 9 Commercial system 11 Rotation sensor 12-15 Voltage sensor 16-17 Current sensor 18-19 Voltage sensor 21-26 Diode 27 to 32 Switching element 33 to 38 Free wheel diode 51 Converter 52 to 57 Switching element 58 to 63 Free wheel diode 71 Control unit 72A, 72B Output power command calculation unit 73 Output voltage effective value calculation unit 74 Divider 75 System voltage phase calculation Unit 76A, 76B Three-phase voltage command calculation unit 77 Gate signal generation unit 81 Three-phase-dq coordinate conversion unit 82A, 82B Current command generation unit 83-84 Subtractor 85-86 PI control unit 87 dq coordinate-3 phase conversion unit

Claims (3)

  A generator driven by a windmill, a rectifier that converts the alternating current output of the generator into direct current, a filter capacitor connected to the output of the rectifier, and a plurality of switching elements constitute a multi-phase circuit, System inverter connected to the output, AC reactor and AC capacitor for converting the rectangular wave voltage output from the system inverter into a sine wave, and the output of the AC reactor to connect and release the commercial system A commercial system open contactor, a rotation sensor that detects the number of revolutions of the generator, a first voltage sensor that detects a voltage applied to the filter capacitor, and a second that detects a voltage on the output side of the AC reactor. Voltage sensor, a current sensor for detecting a current output to the commercial system, a third voltage sensor for detecting the voltage of the commercial system, and the rotation sensor Means for calculating an output power command based on the number of revolutions, means for calculating an effective value of the output voltage based on the voltage detected by the second voltage sensor for detecting the voltage on the output side of the AC reactor, and the output power A means for calculating an output current command based on the command and an effective value of the output voltage; a means for calculating a voltage phase based on a voltage detected by the third voltage sensor for detecting a voltage of a commercial system; and the output current command and the voltage Based on the phase and output current, the three-phase voltage command for calculating the three-phase voltage command output from the system inverter, and the voltage applied to the filter capacitor and the carrier signal to the plurality of switching elements constituting the inverter. In a wind turbine generator having means for generating a gate signal, the power output from the system inverter is controlled based on the rotational speed of the generator. Wind power generator characterized by things.   In Claim 1, the power factor command from the outside is input into the output power command calculation unit, and the power factor is not fixed but variable, thereby preventing a voltage rise on the commercial system side. Wind power generator. In claim 1, the calculation of the output power command is not a constant function with respect to the generator rotational speed, but by using the maximum power point tracking control method, it is possible to extract power from the windmill more efficiently. A featured wind power generator.

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