JP4299767B2 - Water turbine power generation system and inverter - Google Patents

Description

  The present invention relates to a hydroelectric power generation system having a permanent magnet synchronous generator in micro hydroelectric power generation.

In recent years, micro hydroelectric power generation with a power generation amount of about 100 kWh or less has attracted attention as new energy. Conventional water turbines control the operation of the water turbine by operating the guide vanes with a governor mechanism, but this structure is complicated and expensive, so it cannot be applied to a micro water turbine. In other words, the micro water turbine is characterized by its small size and low price without a governor mechanism. However, since it does not have a speed control function, the micro water turbine operates only at one specification point, and thus has a drawback that it cannot be applied to water resources that have a flow rate change. As a technique for improving this, there is Patent Document 1 (automatic operation control device for a water turbine generator). This technology is composed of a turbine, a permanent magnet synchronous generator driven by the turbine, and an inverter for controlling the rotational speed of the generator. Since this inverter controls the rotational speed of the generator in response to changes in the flow rate of the turbine, the turbine has the advantage that it can always maintain the optimum operating state and the operating range is expanded. This operation method is called an optimum operation control variable speed power generation system.
JP 2004-183618 A

  A three-phase AC type is generally used as the permanent magnet synchronous generator of the optimum speed control variable speed power generation system. If the three phases are mixed and wired when the generator is installed, the speed command from the inverter is in the reverse rotation direction, which reverses the impeller of the water wheel. At this time, since the density of water that is the working fluid of the turbine is 1000 times the density of air that is the working fluid of the windmill, a large inertial force acts on the impeller. As a result, an excessive current flows through the stator of the generator at a speed that cannot be handled by the overcurrent trip function of the inverter, and the magnetic flux of the permanent magnet is lost due to the demagnetizing field generated by the current. When the demagnetizing field is removed, the magnetic flux is only partially recovered, and this phenomenon is called demagnetization. Once demagnetized, not only does the power generation efficiency drop significantly, which causes a problem, but depending on the demagnetization level, it becomes uncontrollable. The same applies even if the impeller of the water wheel rotates backward for some reason.

  An object of the present invention is to provide a hydroelectric power generation system and an inverter having protection means for preventing demagnetization of a permanent magnet even if a reverse rotation of an impeller due to erroneous wiring or the like at the time of installing a generator occurs.

  The present invention provides a hydroelectric power generation system including a water turbine, a permanent magnet synchronous generator driven by the water turbine, and an inverter that controls rotation by measuring a rotation speed of the power generator, and the inverter includes the power generation This is a hydraulic power generation system that detects the rotation direction of the generator based on the output of the machine and stops the power generation control when the detected rotation direction is opposite to the set rotation direction in the rotation control.

  Further, the present invention relates to a hydroelectric power generation system including a water turbine, a permanent magnet synchronous generator driven by the water turbine, and an inverter that controls rotation by measuring a rotation speed of the generator, and the inverter includes: Based on the output of the generator, the rotation direction of the generator is detected, and if the detected rotation direction is opposite to the set rotation direction in the rotation control, rotation control that is opposite to the set rotation direction is performed. It is a hydroelectric power generation system.

  And this invention is a hydroelectric power generation system which has the grid connection apparatus which returns generated electric power to a power supply.

  Furthermore, the present invention is an inverter that measures the rotational speed of a permanent magnet synchronous generator driven by a water turbine, controls the rotation and generates power, and detects the rotational direction of the generator based on the output of the generator. When the detected rotation direction is opposite to the set rotation direction in the rotation control, the inverter stops power generation control.

  According to the present invention, in an inverter that controls the rotation by measuring the rotation speed of a permanent magnet synchronous generator driven by a turbine, the rotation direction of the generator is detected based on the output of the generator. When the detected rotation direction is opposite to the set rotation direction in rotation control, the inverter performs rotation control that is opposite to the set rotation direction.

  According to the present invention, it is possible to obtain a hydroelectric power generation system and an inverter having protection means for preventing demagnetization of a permanent magnet even if a reverse rotation of an impeller due to erroneous wiring or the like at the time of installing a generator occurs.

The best mode for carrying out the present invention will be described.
Embodiments of the water turbine power generation system and the inverter according to the present invention will be described below with reference to FIGS. The best mode is Example 1.

  Example 1 will be described. FIG. 1 is a system system and circuit diagram of the first embodiment. Reference numeral 2 denotes a water wheel provided in the pipe 1 operated by the potential energy of water, and reference numeral 3 denotes a permanent magnet synchronous generator that operates by generating torque generated by the water wheel. The output signal 14 of the inlet pressure sensor 12 and the output signal 15 of the outlet pressure sensor 13 are input to the pressure calculator 5 of the inverter 4, and the pressure calculator 5 determines the pressure difference between the turbine inlet and outlet. The inverter 4 includes a pressure calculator 5, an operation commander (with rotation stop command) 7, a rotation speed command generator 8, a power converter 9, a rotation direction / rotation speed detector 11, a capacitor 17, and the like. The generator 3 is connected to terminals U, V, and W, and the generator 3 is controlled to rotate so that the rotation speed of the generator 3 is smaller than the rotation speed due to the torque generated by the water turbine 1. The generated power is taken in through the flywheel diode 16 by regenerative control of the inverter 4 and stored as DC power 10 between P and N (accumulated in the capacitor 17. For example, if the generated voltage of the generator is 200V AC, the inverter P, The voltage between N (DC voltage) is 280V.) The electric power generated by the generator 3 is DC-transmitted from the DC terminals P and N of the inverter 4 to the load (inverter) 6.

  The rotation direction and rotation speed of the generator 3 are detected by a rotation direction / rotation speed detector 11. The detection method is performed based on the waveform of the output voltage of the generator 3 or the like. Information on the rotation direction and the rotation speed detected here is passed to the operation command device 7, and after the operation command device 7 determines whether or not the operation is possible, the operation command such as the target rotation speed or the rotation stop is generated. Is input to the device 8. The rotation speed command generator 8 receives an operation command such as a target rotation speed or rotation stop, generates a series of rotation speed commands or a rotation stop command from the current rotation speed so as to become the target rotation speed, and the power converter Output to 9. The power converter 9 controls the rotation speed of the generator 3 according to the received rotation speed command or rotation stop command. Note that the rotation direction of the generator 3 is detected outside the inverter 4, and the inverter 4 can control the rotation speed of the generator 3 based on the detected information on the rotation direction.

  An example of the operation control method in the water turbine power generation system of the present embodiment is shown in a flowchart in FIG. When starting the power generation operation, the rotation direction / rotation speed detector 11 first detects the rotation direction and rotation speed of the generator 3 (S101), and whether the rotation direction is the positive direction (set rotation direction in the rotation control). Judgment is made (S102). When the detected rotation direction is normal rotation, the operation command unit 7 outputs a normal rotation operation command to the rotation speed command generator 8 (S121), and the generator rotation is performed from the current rotation speed to the target rotation speed. Frequency control is performed by the power converter 9 so as to control the speed (S122), and thereafter power generation control is performed (S123). On the other hand, when the detected rotation direction is reverse rotation (reverse to the set rotation direction in the rotation control), the operation command unit 7 outputs a rotation stop command to the rotation speed command generator 8 (S111), and an alarm is issued. A signal is output (S112), and the power generation operation is not performed.

  The water turbine power generation system according to the first embodiment makes it possible to determine whether the rotation direction of the generator is normal or reverse at the start of power generation control or the like, and to prevent the generator from performing power generation control during reverse rotation due to reverse wiring connection or the like. It is possible to avoid demagnetization of the permanent magnet used in the generator.

  A second embodiment will be described. FIG. 3 is a system system and circuit diagram of the second embodiment. The operation of the component equipment is the same as that of the first embodiment, and the differences will be mainly described. In this embodiment, when the detected rotation direction is reverse rotation (reverse to the set rotation direction in the rotation control), the operation command device (with reverse rotation command) 18 sends a reverse rotation command (reverse to the set rotation direction). Rotation control) is output to the rotation speed command generator 8, and the power converter 9 performs frequency control of reverse rotation.

  An example of the operation control flowchart in the second embodiment is shown in FIG. When starting the power generation operation, first, the rotation direction / rotation speed detector 11 detects the rotation direction and rotation speed of the generator 3 (S201), and whether the rotation direction is the positive direction (set rotation direction in the rotation control). Judgment is made (S202). When the detected rotation direction is normal rotation, the operation command unit 7 outputs a normal rotation operation command to the rotation speed command generator 8 (S221), and the generator rotates from the current rotation speed to the target rotation speed. Frequency control is performed by the power converter 9 so as to control the speed (S222), and thereafter power generation control is performed (S223). On the other hand, when the detected rotation direction is reverse rotation (reverse to the set rotation direction in the rotation control), the operation command unit 7 outputs a reverse rotation command to the rotation speed command generator 8 (S211). In step S222, the rotational speed control up to the target rotational speed is performed in the same manner as in the forward rotation, and thereafter, the power generation operation is performed (S223).

  Even if the wiring connection between the generator 3 and the inverter 4 is reversely connected by the water turbine power generation system of the present embodiment, the inverter 4 performs frequency control in the rotation direction according to the connection, and the generator 3 is normal. Therefore, the demagnetization of the permanent magnet used in the generator 3 can be avoided.

  A third embodiment will be described. FIG. 3 is a system system and circuit diagram of the third embodiment. In this embodiment, as compared with the first embodiment, a grid interconnection device 19 is used instead of the load (inverter) 6, and the operation and effect are the same as those of the first embodiment, and the description thereof is omitted.

  Example 4 will be described. FIG. 4 is a system system and circuit diagram of the fourth embodiment. In this embodiment, as compared with the second embodiment, the system interconnection device 19 is used instead of the load (inverter) 6, and the operation and effect are the same as those of the second embodiment, and the description thereof is omitted.

  As described above in the embodiments, according to the present invention, when the wiring between the generator and the inverter is connected in the wrong phase, or when the inlet / outlet of the water turbine is installed in reverse, the working fluid flows through the water turbine. Even when the direction of the rotation is reversed and the impeller is rotated in reverse, the voltage waveform of reverse rotation that occurs when incorrect wiring or incorrect installation can be detected before starting power generation control, etc. An excessive current does not flow through the magnet synchronous generator. Thereby, the permanent magnet of a generator does not demagnetize and it can prevent a power generation efficiency fall and an uncontrollable state. In addition, it is possible to avoid a large-scale work of returning to the factory and repairing when demagnetized. At the same time, it is possible to prevent an excessive current flowing through the inverter and the control device for controlling them, and to prevent damage to the equipment due to the overcurrent. The present invention can also be used for wind power generation systems.

BRIEF DESCRIPTION OF THE DRAWINGS The system system | strain and circuit diagram of the hydroelectric power generation system of Example 1. FIG. The flowchart figure of an example of the electric power generation control in the hydroelectric power generation system of Example 1,3. The system system | strain and circuit diagram of the hydroelectric power generation system of Example 2. FIG. The flowchart figure of an example of the electric power generation control in the hydraulic power generation system of Example 2,4. The system system | strain and circuit diagram of the hydroelectric power generation system of Example 3. FIG. The system system | strain and circuit diagram of the hydroelectric power generation system of Example 4. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Water piping 2 ... Water wheel 3 ... Generator 4 ... Inverter 5 ... Pressure calculator 6 ... Load (inverter),
7 ... Operation command device (with rotation stop command)
DESCRIPTION OF SYMBOLS 8 ... Rotational speed command generator 9 ... Power converter 10 ... DC power 11 ... Rotation direction and rotational speed detector 12 ... Inlet pressure sensor 13 ... Outlet pressure sensor 14 ... Inlet pressure sensor output signal 15 ... Outlet pressure sensor output signal 16 ... Flywheel diode 17 ... Electrolytic capacitor 18 ... Operation command (with reverse rotation command)
19 ... Grid interconnection device

Claims (5)

In a hydroelectric power generation system having a water wheel, a permanent magnet synchronous generator driven by the water wheel, and an inverter that controls rotation by measuring the rotation speed of the power generator,
The inverter detects the rotation direction of the generator based on the output of the generator, and stops the power generation control when the detected rotation direction is opposite to the set rotation direction in the rotation control. Hydropower generation system. In a hydroelectric power generation system having a water wheel, a permanent magnet synchronous generator driven by the water wheel, and an inverter that controls rotation by measuring the rotation speed of the power generator,
The inverter detects the rotation direction of the generator based on the output of the generator, and when the detected rotation direction is opposite to the set rotation direction in rotation control, the inverter is opposite to the set rotation direction. A hydroelectric power generation system characterized by performing rotation control.   The hydroelectric power generation system according to claim 1, further comprising a grid interconnection device that returns generated power to a power source. In an inverter that measures the rotation speed of a permanent magnet synchronous generator driven by a turbine and controls the rotation,
An inverter that detects a rotation direction of the generator based on an output of the generator and stops the power generation control when the detected rotation direction is opposite to a set rotation direction in the rotation control. In an inverter that measures the rotation speed of a permanent magnet synchronous generator driven by a turbine and controls the rotation,
Based on the output of the generator, the rotation direction of the generator is detected, and if the detected rotation direction is opposite to the set rotation direction in the rotation control, rotation control that is opposite to the set rotation direction is performed. An inverter characterized by that.

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