JP2014150597A - Inverter device for wind generator system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wind generator system capable of constantly continuing an output of desired generated power regardless of states of a generator.SOLUTION: In the inverter device 3, a power command value computing device 14 computes a power command value ωT from a speed detection value ω and a torque command T. A generated power computing device 15 computes an actual generated power value IV output from the generator 2 on the basis of an output current detection value I and an output voltage detection value V of the generator 2. The inverter device 3 computes a correction torque Tc on the basis of a difference between the power command value ωTand the actual generated power value IV and adds the correction torque Tc to a torque command T.

Description

  The present invention relates to an inverter device adapted for a wind power generator, and more particularly to a device for converting generator power into DC power.

  FIG. 5 is a schematic diagram showing a configuration of a conventional wind turbine power generation system. The windmill controller 7 determines the generated power of the wind power generation system according to the wind speed received by the windmill 1 and the rotation speed of the windmill 1, and calculates the necessary torque of the generator 2 according to this. This torque value is transmitted to the inverter device 3 (inverter control unit 8).

  The inverter device 3 includes an inverter forward converter 4, an inverter reverse converter 5, and an inverter control unit 8. Then, the inverter device 3 causes the generator 2 to generate the electric power requested by the windmill controller 7 by causing the generator 2 to generate the torque value received from the windmill controller 7. In addition, the command value to the inverter reverse converter 5 is a torque, and the command value to the inverter forward converter part 4 is a DC voltage and a power factor.

JP 2008-29082 A

The windmill controller 7 calculates the torque amount (torque command T ^* ) that the generator 2 should output based on the current generator rotational speed and wind speed.

The inverter device 3 inputs the torque command T ^* received from the wind turbine controller 7 to the inverter control unit 8 and calculates the current command I ^* . The inverter reverse converter 5 outputs a current according to the current command I ^* and causes the generator 2 to generate torque.

  However, the induced voltage generated in the generator 2 often decreases in proportion to the temperature. Due to this phenomenon, even when the inverter device 3 passes a constant current through the generator 2, the temperature change of the generator 2 occurs. The torque generated by this changes.

For this reason, if the inverter control unit 8 simply converts the torque command T ^* received from the wind turbine controller 7 into the current command I ^* and outputs it to the generator 2, a deviation occurs between the desired power and the actual generated power. End up.

  FIG. 6 shows the wind speed-generated power characteristics of the wind power generation system. Since it is desirable for the wind power generation system to generate power according to the desired amount of power indicated by the solid line, it can be said that it is not desirable that a difference between the desired power and the actual generated power occurs due to the influence of the generator 2.

  In addition, when a wind of a rated wind speed or higher is blowing, it is particularly desirable to generate power according to the rated generated power.

  As described above, in the wind power generation system, it is a problem to always output desired generated power regardless of the state of the generator.

  The present invention has been devised in view of the above-described conventional problems, and one aspect thereof is a wind turbine that converts wind into rotational energy, a generator that converts rotational energy of the wind turbine into electric energy, and a generator A wind turbine controller that calculates the torque command output to the generator based on the rotational speed and wind speed, and calculates the current command from the torque command, and controls the generated power of the generator based on the current command to generate torque in the generator An inverter device that interconnects the generator and the grid, wherein the inverter device calculates a power command value from the speed detection value and the torque command, and outputs the generator The actual generated power output from the generator is calculated from the detected current value and the detected output voltage, and the correction torque is calculated based on the difference between the power command value and the actual generated power. Characterized by adding to the command.

  Further, as one aspect, when the actual generated power exceeds the desired power, the amount exceeding the limit power is used as a limit torque, and the limit torque is subtracted from a value obtained by adding the correction torque to the torque command.

  According to the present invention, in a wind power generation system, it is possible to always output desired generated power regardless of the state of the generator.

It is the schematic which shows the structure of the windmill electric power generation system in embodiment. It is a block diagram which shows the inverter control part in embodiment. It is a block diagram which shows the generated electric power correction amount calculator in embodiment. It is a block diagram which shows the generated electric power limit amount calculator in embodiment. It is the schematic which shows the structure of the conventional windmill electric power generation system. It is a graph which shows the wind speed-generated electric power characteristic of a wind power generation system.

  Hereinafter, the inverter apparatus of the wind power generation system in embodiment of this invention is demonstrated in detail based on drawing.

[Embodiment]
FIG. 1 is a schematic diagram showing a configuration of a wind turbine power generation system in the present embodiment. As shown in FIG. 1, the wind turbine power generation system according to the present embodiment includes a wind turbine (not shown) that converts wind into rotational kinetic energy, a generator 2 that converts rotational kinetic energy of the wind turbine into electric energy, and a generator 2. Inverter converter 5 that converts the AC power into DC power, inverter forward converter 4 that converts the DC power into AC power, and inverters (inverter inverter 5 and inverter forward converter 4) are controlled. An inverter control unit 8 and a windmill controller 7 that controls the entire wind power generation system are provided.

  The inverter reverse converter unit 5, the inverter forward converter unit 4, and the inverter control unit 8 are integrated to form an inverter device 3. The inverter device 3 controls the power generated by the generator 2 and interconnects the generator 2 and the system 6.

Further, the windmill controller 7 includes a torque command calculator 9 that calculates a torque command T ^* based on the rotational speed ω and wind speed of the generator 2, and the calculated torque command T ^* is output to the inverter control unit 8. .

The inverter control unit 8 corrects the torque command T ^* in a control block shown in FIG. Based on the corrected torque command T ^* + Tc−Tl, the inverter current command calculator 11 calculates the current command I ^* and outputs it to the inverter inverse converter 5. The inverter reverse converter 5 outputs a current according to the current command I ^* and causes the generator 2 to generate torque.

FIG. 2 shows a control block for correcting the torque command T ^* . It is assumed that the control block is provided in the inverter control unit 8. This control block controls generated power to a desired value. As shown in FIG. 2, the control block includes a power command calculator 14, a generated power calculator 15, a generated power correction amount calculator 16, and a generated power limit amount calculator 17.

The power command calculator 14 calculates a desired power amount (power command value ωT ^* ) based on the torque command value T ^* received from the wind turbine controller 7 and the speed detection value ω. Further, the generated power calculator 15 calculates the actual generated power IV based on the detected current value I and the detected voltage value V between the generator 2 and the inverter inverse converter 5. Then, the generated power correction amount calculator 16, the power command value .omega.T ^* and the correction torque Tc to eliminate the difference between the actual generated power actual generated power IV from the binary power command value .omega.T ^* the IV is determined.

As shown in FIG. 3, the generated power compensation calculator 16 includes a subtractor, a proportional calculator 20, an integral calculator 21, and a constant multiplier 22. First, the generated power compensation calculator 16 subtracts the actual generated power IV from the power command value ωT ^* in the subtractor. Then, the power command value ωT ^* and the difference ωT ^* −IV between the actual power generation are output to the proportional calculator 20 and the integral calculator 21. Next, the proportional calculator 20 performs a proportional operation on the deviation ωT ^* -IV, an integral calculator 21 performs an integral operation on the deviation ωT ^* -IV, and adds the outputs of the proportional calculator 20 and the integral calculator 21 together. . Then, this value is multiplied by a constant set in advance by a constant multiplier 22 and output as a correction torque Tc.

By adding the correction torque Tc to the torque command T ^* , the actual generated power IV can be controlled in accordance with the power command value ωT ^* . The control method so far is referred to as “generated power constant control”.

  Further, as shown in FIG. 2, the difference rP-IV between the rated power value rP and the actual generated power IV is calculated, and when the difference rP-IV is negative, the power is generated above the rated power value rP. Therefore, it is necessary to reduce the actual generated power IV. For this reason, the rated power value rP and the actual generated power IV are input to the generated power limit amount calculator 17 to calculate the generated power limit torque Tl.

  As shown in FIG. 4, the generated power limit amount calculator 17 includes switches SW 1, SW 2, a zero output device 23, an integral calculator 24, and a proportional calculator 25. Then, the difference rP-IV between the rated power value rP and the actual generated power IV is taken. When the difference rP-IV is positive (≧ 0), the switches SW1 and SW2 are switched upward, and the difference rP-IV is negative (< In the case of 0), the switches SW1 and SW2 are switched to the lower side. When the deviation rP-IV is positive (≧ 0), it is assumed that the actual generated power IV is smaller than the rated power value rP, and 0 is output from the zero output device 23, and 0 is output as the limit torque Tl.

  On the other hand, when the difference rP-IV is negative (<0), the actual generated power IV is larger than the rated power rP. Therefore, the integral calculator 24 integrates the deviation rP-IV, the proportional calculator 25 proportionally calculates the deviation rP-IV, and the output of the integral calculator 24 and the proportional calculator 25 is added to generate power limit torque. Output as Tl.

By subtracting the generated power limit torque Tl from the torque command (T ^* −Tc), the actual generated power IV can be controlled so as not to exceed the rated power rP. This function is called “Generated power limit function”.

  In the “generated power constant control”, the constant multiplier in the generated power guarantee computing unit 16 is set to a value of 1 or more so that the correction torque Tc becomes a higher value. By operating the “limit function”, it is possible to reliably output the rated generated power when the wind speed is higher than the rated wind speed.

As described above, according to the wind power generation system in the present embodiment, since the actual generated power IV is controlled according to the power command ωT ^* from the “generated power constant control”, a desired power generation is possible regardless of the state of the generator. It becomes possible to continuously output power.

  Further, the “generated power limit function” enables control so that the actual generated power IV does not exceed the rated generated power.

  Furthermore, by using the “generated power constant control” and the “power generation limit function” in combination, it is possible to continue outputting desired power and to reliably output rated generated power when the wind speed is higher than the rated wind speed.

  Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

  In the embodiment, the input of the generated power limit amount calculator 17 is the rated power value rP so that the rated generated power can be output when the wind speed exceeds the rated wind speed as the “generated power limit function”. Instead, a desired power value may be input.

DESCRIPTION OF SYMBOLS 1 ... Windmill 2 ... Generator 3 ... Inverter device 6 ... System 7 ... Windmill controller T ^* ... Torque command I ^* ... Current command ω ... Speed detection value ωT ^* ... Electric power command value I ... Output current detection value V ... Output voltage detection Value IV ... Actual generated power Tc ... Correction torque Tl ... Limit torque

Claims (2)

A windmill that converts wind into rotational energy;
A generator that converts the rotational energy of the windmill into electric energy;
A windmill controller that calculates a torque command output to the generator based on the rotational speed and wind speed of the generator;
An inverter device that calculates a current command from the torque command, controls the generated power of the generator based on the current command to generate torque in the generator, and interconnects the generator and the system;
A wind power generation system comprising:
The inverter device is
The power command value is calculated from the speed detection value and the torque command, the actual power output from the generator is calculated from the output current detection value and the output voltage detection value of the generator, and the power command value and the actual power generation An inverter device for a wind power generation system that calculates a correction torque based on the difference between the two and adds the correction torque to a torque command.   2. The wind power generation system according to claim 1, wherein when the actual generated power exceeds the desired power, the amount exceeding the limit torque is used as a limit torque, and the limit torque is subtracted from a value obtained by adding the correction torque to the torque command. Inverter device.

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