JP2019193513A - Hydraulic power generation system interconnection system - Google Patents

Abstract

To provide a hydraulic power generation system interconnection system that includes a function unit for system interconnection for which a general-purpose item can be used to enable cost reduction while securing quality.SOLUTION: A hydraulic power generation system interconnection system comprises a hydraulic turbine 1, a power generator 3, a rectifier 15, a power conditioner 8 capable of interconnecting with a system 9, and a controller 4. The power conditioner 8 is an integrated general-purpose item, for example, a power conditioner for photovoltaic power generation. The hydraulic power generation system interconnection system may comprise a consumption resistance device 7 and fail-safe control means 23.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hydroelectric power generation system interconnection system in which a hydroelectric power generation apparatus such as a small hydropower generation apparatus is linked to an AC commercial power system.

  A hydroelectric generator is a system that uses the kinetic energy of running water for power generation. The main configuration includes a water wheel that rotates in response to a flow of water, a generator that is connected to the water wheel to convert rotational energy into electric energy, a power generator output, and a control device that controls the water wheel. Since the optimum power to be extracted from the generator varies depending on the flow velocity, the control device measures the flow velocity, the rotation speed of the turbine or the generated voltage of the generator, determines the optimum power to be extracted from the generator, and determines the generator power. Control so that the quantity and the optimum value match.

  A grid-connected system that sells power generated by hydroelectric power linked to an AC commercial power grid (hereinafter sometimes simply referred to as “grid”) has a maximum efficiency torque so that the output of the generator is maximized. In order to control the rotational speed, it consists of a synchronous generator, a generator control means (generator control driver) dedicated to the synchronous generator, and an output voltage control means (system-connected inverter). It is a specially designed device.

  For example, as shown in FIG. 4, the power conversion circuit 52 that converts the output of the three-phase alternating current of the generator 51 of the hydroelectric generator into direct current, the generator control means 53 that is the control means, and the direct current according to the system 54 A grid interconnection system is constituted by a grid interconnection inverter composed of an inverter 55 that converts AC power and its output voltage control means 56 (for example, Patent Document 1).

JP 2007-6553 A

The configuration of a conventional grid-connected hydroelectric power generation system includes a synchronous generator, a generator control means (generator control driver) dedicated to the synchronous generator, and an output voltage control means (system-connected inverter). Because it is a specially designed device tailored to the equipment, the equipment is expensive.
Therefore, in the power generation device for small power generation installed in irrigation channels such as agricultural water and industrial water, so-called small hydroelectric power generation device, the ratio of the cost occupied by electrical equipment for grid connection in the entire system increases. It is uneconomical.

  SUMMARY OF THE INVENTION The present invention solves the above problems, and an object of the present invention is to provide a hydroelectric power grid interconnection system in which a general-purpose product can be used as a means for grid interconnection, and the cost can be reduced while ensuring quality. That is.

The hydropower system interconnection system of the present invention includes a water turbine 1, a generator 3 that converts rotational energy of the water turbine 1 into electric energy, a rectifier 15 that converts the generated power of the generator 3 into DC power, and the rectifier 15 includes a power conditioner 8 that converts the DC power rectified in 15 into AC power that can be connected to the grid 9, and a control device 4 that controls the rotational speed of the water turbine 1 by adjusting the load of the generator 3. ,
The power conditioner 8 is an integral general-purpose product.

According to this configuration, the control for changing the rotation speed of the water turbine 1 by adjusting the load of the generator 3 is performed by controlling the maximum power point control (MPPT control) of the control device 4 and the power conditioner 8 provided separately from the power conditioner 8. ) And the like, and the generated power converted into direct current is supplied to the power conditioner 8 by performing the AC / DC conversion control in the control device 4, so that the general-purpose power conditioner 8 can be used. .
In this way, since the integrated general-purpose power conditioner 8 is used as it is for the equipment that links the generated power to the grid 9, it is cheaper than the case of using a specially designed equipment while ensuring quality. It is possible to provide a power generation system.
The “general-purpose product” referred to in this specification is not designed exclusively for a specific type of power generator, but is a range of power and voltage that can be processed by the input, and the voltage of the grid 9 that is connected. And if the frequency is matched, it means that the device is applicable. An “integrated general-purpose product” refers to a general-purpose product in which all components are incorporated in a common housing and can be handled as a single object.

The power conditioner 8 may be a general-purpose product for connection to the solar power generation system 9. That is, the power conditioner 8 which connects the solar cell panel with which the photovoltaic cell was combined with the system | strain 9 may be sufficient.
Photovoltaic power generation is spreading, and many power conditioners 8 for grid interconnection are commercially available at low cost and high quality due to mass production effects. By using such a commercially available power conditioner 8, it is possible to construct an even more inexpensive and high-quality hydropower system interconnection system.

In the present invention, the rectifier 15 includes a rectification function unit 15a that rectifies the rectifier 15 and a switch function unit 14 that turns on and off the input of the power generated by the generator 3 to the rectification function unit 15a. It may be.
If the rectifier 15 for rectifying the generated power has a switch function for turning it on and off, the generator 3 and the system 9 can be disconnected, and it is possible to cope with overvoltage power caused by high-speed rotation of the turbine 1 or power failure of the system 9. Becomes easier.

In the present invention, a consumption resistance device connected between the generator 3 and the power conditioner 8 and absorbing overvoltage power by resistance, and when the generated power of the generator 3 becomes an overvoltage higher than a set voltage, Consumption resistance control means for causing the consumption resistance device to absorb overvoltage power generated in the power generated by the generator 3 may be provided.
When the consumption resistance device and the consumption resistance control means are provided in this way, it is possible to absorb the overvoltage power generated by the high speed rotation of the water turbine 1 or the power failure of the system 9, and this hydraulic power system interconnection system is configured. Degradation and damage due to overvoltage of the equipment can be prevented.

In this invention, voltage detection means for measuring the voltage rectified by the rectifier 15 of the generator 3;
Current detection means 17 for measuring the current rectified by the rectifier 15 of the generator 3;
Voltage detection means 18 for measuring the voltage rectified by the rectifier 15 of the generator 3;
Rotational speed detection means 19 for detecting the rotational speed of the generator 3 from the frequency of the generated power of the generator 3;
It is determined from the voltage, current, and rotation speed detected by the voltage detection means 18, the current detection means 17, and the rotation speed detection means 19, and the start, stop, and abnormal signals output from the power conditioner 8. Fail-safe control for performing either one or both of shutting off the input to the rectifier 15 of the generator 3 and braking of the braking means (10) provided in the generator 3 when the protection operation condition is satisfied. The structure which has the means 23 may be sufficient.
By having such a fail-safe control means 23, it is possible to prevent the deterioration and damage due to the overvoltage of the devices constituting this hydroelectric power generation system interconnection system even better.

  The hydropower system interconnection system of the present invention includes a water turbine, a generator that converts rotational energy of the water wheel into electric energy, a rectifier that converts the generated power of the generator into DC power, and DC power that is rectified by the rectifier. A power conditioner that converts AC into AC power that can be connected to the grid, and a control device that controls the rotational speed of the water turbine by adjusting the load of the generator, and the power conditioner is an integrated general-purpose product Therefore, it is possible to reduce the cost while ensuring the quality.

It is a block diagram which shows the conceptual structure of the hydroelectric power system interconnection system which concerns on one Embodiment of this invention. It is a block diagram of the specific example of the same hydroelectric power generation system interconnection system. It is a block diagram which shows the conceptual structure of the power conditioner for solar power generation used for the same hydroelectric power system connection system. It is an electric circuit diagram of a conventional example.

An embodiment of the present invention will be described with reference to FIGS. The hydroelectric generator shown in FIG. 1 is an example of a hydroelectric generator in which the hydraulic turbine 1 is a horizontal axis type (propeller type). The water wheel 1 is a relatively small water wheel installed in a waterway such as agricultural water, industrial water, or water and sewage. The water wheel 1 is rotated by the kinetic energy of water, and the main shaft 1 a of the water wheel 1 rotates the generator 3. A hydroelectric generator 2 is constituted by the turbine 1 and the generator 3. The hydroelectric generator 2 is provided with braking means such as an electromagnetic brake 10 that brakes the water turbine 1 or the generator 3.
The generator 3 is connected to the system 9 via the control device 4 and the power conditioner 8. The system 9 is an AC commercial power system, for example, 100V or 200V, 50 or 60 Hz low voltage wiring.
The water turbine 1, the generator 3, the control device 4, and the power conditioner 8 constitute a hydroelectric power system interconnection system.

  The generator 3 is a three-phase synchronous generator using a permanent magnet, and is fastened to the main shaft 1a by a coupling (not shown) or the like. A speed increaser (not shown) is provided between the main shaft 1a and the generator 3 as necessary. When a load is connected to the generator 3 and an output is taken, torque is applied to the turbine 1 from the generator 3, and the rotation of the turbine 1 is braked. When the load is increased, the rotation speed of the water turbine 1 is decreased. When the load is decreased, the rotation speed of the water turbine 1 is increased. A control device 4, a power conditioner 8, and a system 9 are connected as a load of the generator 3.

  The control device 4 and the power conditioner 8 increase or decrease the torque of the generator 3 in accordance with the flow velocity of the water channel so as to control the water turbine 1 to rotate at an optimum rotational speed. The flow velocity of the water channel is detected by an anemometer 25. Instead of the flow rate or in combination with the flow rate, the torque of the generator 3 may be increased or decreased according to the rotation speed of the water turbine 1 or the rotation speed of the generator 3. The rotational speed of the generator 3 may be detected from the frequency of the generated power. The rotational speed of the water turbine 1 and the rotational speed of the generator 3 are in a fixed relationship, and if one of them can be detected, the other can be found by calculation.

  The control device 4 includes a main circuit unit 6, a control circuit unit 5 that controls the main circuit unit 6, and a consumption resistance device 7. The main circuit unit 6 is provided with a rectifier 15 that converts the three-phase AC power of the generator 3 into a direct current and a DC / DC converter 16 that boosts the rectified direct current. The DC / DC converter 16 uses, for example, a voltage that can control the voltage on the secondary side that is the boost side by a control input.

The power conditioner 8 is a device connected in parallel to the grid 9 and converts the input DC power into AC power having a voltage (slightly higher voltage), frequency, and phase equivalent to those of the grid 9.
As this power conditioner 8, an integral general-purpose product is used. That is, a general-purpose product that can be handled as an integrated device in which components (not shown) are housed in a housing is used. In this embodiment, as the power conditioner 8, a power conditioner that is mass-produced for photovoltaic power generation that converts the generated power of the photovoltaic power generation into AC power that can be connected to the grid 9 is used.

  FIG. 3 shows an example of a power conditioner 8 for photovoltaic power generation used in this embodiment. The power conditioner 8 includes a DC / DC converter 31, a DC / AC inverter 32, and a control means 33. The DC / DC converter 31 is a means for boosting the input DC power to a voltage corresponding to the voltage of the system 9, and the output voltage is variable. The input voltage of the DC / DC converter 31 is the output voltage of the solar cell module 36 which is the original use of the power conditioner 8, and is the voltage output for grid connection in general solar power generation. One of the voltages (for example, single phase 100 / 200V or three phase 200V) is used. The DC / AC inverter 32 converts the DC power output from the DC / DC converter 31 into AC power having a frequency and phase that can be linked to the system 9.

  The control means 33 includes a power control unit 34 and a maximum power point control unit 35. The power control unit 34 performs basic control on the DC / DC converter 31 and the DC / AC inverter 32. The maximum power point control unit 35 gives a command to the power control unit 34 so as to perform maximum power point tracking control (MPPT control) by the hill-climbing method.

The MPPT control will be described. The amount of power generated by a power generation device such as the solar cell module 36 is determined by the product of the voltage and current, but the generated voltage and current vary. In response to this variation, the MPPT control by the maximum power point tracking control unit 35 always searches for an operating point that is a combination of voltage and current so that the maximum output is generated. The power control unit 34 controls the DC / DC converter 31 and the DC / AC inverter 32 so as to work at the operating point obtained by the maximum power point control unit 35 as described above.
In the case of this embodiment, fluctuations in the current and voltage of the power that is rectified and input to the power conditioner 8 occur due to fluctuations in the generated power of the generator 3, and the maximum power point control unit 35 against these fluctuations. Fulfills the above functions.
The control unit 33 may be configured to control the DC / DC converter 31 and the DC / AC inverter 32 by, for example, a pulse width modulation method without providing the maximum power point control unit 35.

FIG. 2 shows a specific configuration example of the control device 4 provided between the generator 3 and the power conditioner 8. In addition to the rectifier 1 and the DC / DC converter 16, the main circuit unit 6 includes an AC / DC control power source 13, an ammeter 17 as current detection means, a rotation speed detection means 19, and a voltmeter 18 as voltage detection means. Have
The rectifier 1 is means for converting the three-phase alternating current generated power of the generator 3 into direct current, and includes a rectifier function unit 15 a that performs this conversion, and a switch function unit 14. The rectifier function unit 15a is composed of a half-bridge circuit in which two semiconductor switching elements (not shown) positioned on the positive potential side and the negative potential side of the output are provided for each phase.

  The switch function unit 14 includes switching elements (not shown) for each phase that open and close a circuit input from the generator 3 to the rectifier function unit 15a. Each switching element of the switch function unit 14 is an element that can be opened and closed by a control input.

The AC / DC control power supply 13 is a power supply for operating the control device 4, converts a part of the AC power generated by the generator 3 into DC power, and supplies the DC power to the control circuit unit 5 and the consumption resistance device 7. Instead of the AC / DC control power supply 13, another power supply such as a battery may be used.
The ammeter 17 detects the current value of the current boosted by the DC / DC converter 16. The voltmeter 18 detects the voltage value of the boosted current. That is, the ammeter 17 and the voltmeter 18 detect the current and voltage input to the power conditioner 8.
The rotation speed detection means 19 detects the rotation speed of the generator 3 from the frequency of the generated current. This detection is performed on the power before rectification of the rectifier 15.

The consumption resistance device 7 is means for consuming electric power generated by the generator 3 for rotation control of the windmill 1, circuit protection, and the like. In this embodiment, the consumption resistance device 7 includes a consumption resistance 7a for short-circuiting the positive potential side wiring and the negative potential side between the DC / DC converter 16 and the power conditioner 8, and the consumption resistance 7a. The switch 7b is connected in series to the switch 7a, and the consumption resistance control means 22 is configured to open and close the switch 7b.
The purpose of the consumption resistance device 7 is that when the grid connection is stopped due to a power failure of the power system while the hydroelectric power generation system is generating power, the system load is no load, the generator 3 is at high speed, and the generated voltage is overvoltage. This is to protect the solar power conditioner 8 by determining that the consumption resistance control means 22 and turning on the switch 7b and consuming overvoltage power with the consumption resistance 7a. The normal state is that the switch b is in the OFF state.

The control circuit unit 5 includes a power generation control unit 12, a brake control unit 11 that controls the electromagnetic brake 10, and a fail-safe control unit 23.
The power generation control means 12 is means for controlling the turbine 1 to rotate at an optimum rotational speed by increasing or decreasing the torque of the generator 3 according to the flow velocity. The power generation control means 12 increases or decreases the generator torque according to a predetermined control rule from the flow velocity of the water channel obtained from the anemometer 25 or the rotation speed of the generator 3 detected by the rotation speed detection means 19. The control signal is generated to control the output voltage of the DC / DC converter. Alternatively, the power control unit 34 in the power conditioner 8 is controlled by the control signal.

  In this case, the MPPT control of the general-purpose / photovoltaic power conditioner 8 is used without modification, and control is performed so that the maximum power at the flow rate can be obtained. At the same time, the control device 4 performs system control such as fail-safe and operation / stop control, and performs control other than MPPT control in the power conditioner 8. Note that the MPPT control of the power conditioner 8 for general purpose / photovoltaic power generation may be stopped and the MPPT control may be performed by the control device 4.

  The fail safe control means 23 is the voltage, current, and rotation speed detected by the voltmeter 18, the ammeter 17, and the rotation speed detection means 19, and the start, stop, and abnormality output by the power conditioner 8. When a predetermined protective operation condition is satisfied from the signal, either the input cutoff to the rectifier 15 of the generator 3 or the braking of the electromagnetic brake 10 which is a braking means provided in the generator 1 is performed. Or do both. The protection operation condition is, for example, when any of the voltage, current, and rotation speed exceeds a threshold value determined for each, and when a stop or abnormal signal is input from the power conditioner 8. .

  The control device 4 and the power conditioner 8 are connected by communication means such as serial communication LAN communication. In addition, the control device 4 includes an external I / O unit 21 that performs serial communication LAN communication with an external device.

According to this configuration, since the integrated general-purpose power conditioner 8 is used as it is for the equipment that connects the generated power to the grid 9, it is less expensive than the case of using a specially designed equipment while ensuring quality. It is possible to provide a hydroelectric power generation system.
In the case where the power conditioner 8 is a power conditioner 8 for solar power generation, it is possible to construct an even more inexpensive and high quality hydroelectric power grid interconnection system. In other words, solar power generation has been widely spread, and many power conditioners for grid interconnection are commercially available with high functionality, durability, and reliability that are inexpensive and of good quality due to mass production effects. By using such a commercially available power conditioner, it is possible to construct an even more inexpensive and high quality hydropower system interconnection system.

In addition, this hydropower system interconnection system has the following advantages.
Since the rectifier 15 that rectifies the generated power has the switch function unit 14, the generator 3 and the system 9 can be disconnected, and the overvoltage power generated by the high-speed rotation of the water turbine 1, the power failure of the system 9, etc. Easy to handle.
Since the consumption resistance device 7 and the consumption resistance control means 22 are provided, it is possible to absorb overvoltage power generated by high-speed rotation of the water turbine 1 or a power failure of the system 9, and this hydraulic power system interconnection system is configured. Degradation and damage due to overvoltage of the equipment can be prevented.
Since the fail-safe control means 23 is provided, deterioration and damage due to overvoltage of the devices constituting the hydroelectric power generation system interconnection system can be prevented even better.

  As mentioned above, although the form for implementing this invention based on embodiment was demonstrated, embodiment disclosed here is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 ... Turbine 2 ... Hydroelectric power generation device 3 ... Generator 4 ... Control device 5 ... Control circuit unit 6 ... Main circuit unit 7 ... Consumption resistance device 8 ... Power conditioner 9 ... System 10 ... Electromagnetic brake 14 ... Switch function unit 15 ... Rectifier 15a ... Rectifier function unit 16 ... DC / DC converter 17 ... Ammeter (current detection means)
18 ... Voltmeter (voltage detection means)
19 ... Rotational speed detection means 23 ... Fail safe control means 35 ... Maximum power point control section

Claims (5)

A turbine, a generator that converts the rotational energy of the turbine into electrical energy, a rectifier that converts the power generated by the generator into DC power, and the DC power rectified by the rectifier is converted into AC power that can be connected to the grid A power conditioner, and a control device for adjusting the load of the generator to control the rotational speed of the water wheel,
The hydropower system interconnection system, wherein the power conditioner is an integrated general-purpose product.   The hydropower system interconnection system according to claim 1, wherein the power conditioner is a general-purpose product for connection to a power generation system of photovoltaic power generation.   3. The hydropower system interconnection system according to claim 1, wherein the rectifier includes a rectification function unit that performs rectification, and a switch function unit that turns on / off input of the generated power of the generator to the rectification function unit. And a hydropower system interconnection system.   The hydroelectric power system interconnection system according to any one of claims 1 to 3, wherein the consumption resistance device is connected between the generator and the power conditioner and absorbs overvoltage power by resistance, and A hydroelectric power grid interconnection system comprising consumption resistance control means for causing the consumption resistance device to absorb the overvoltage power generated in the generated power of the generator when the generated power of the generator becomes an overvoltage that is equal to or higher than a set voltage. The hydroelectric power generation system interconnection system according to any one of claims 1 to 4, wherein a voltage detection unit that measures a voltage rectified by the rectifier of the generator;
Current detection means for measuring the current rectified by the rectifier of the generator;
Current calculating means for calculating the current detected by the current detecting means;
Rotation speed detection means for detecting the rotation speed of the generator from the frequency of the generated power of the generator; Voltage, current, and rotation speed detected by the voltage detection means, the current detection means, and the rotation speed detection means In addition, when a predetermined protective operation condition is satisfied from start, stop, and abnormality signals output from the power conditioner, the input of the generator to the rectifier is shut off and the braking means provided in the generator Fail-safe control means for performing either one or both of braking,
Hydroelectric power system interconnection system.

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