Engine-driven power generation device and engine-driven power generation system

Abstract

To provide an engine-driven power generation device that enables omission of an engine-starting storage battery and a starting electric motor, and achieves cost reduction and space saving.SOLUTION: An engine-driven power generation device of the present invention includes: a synchronous machine that is also used as an AC generator that supplies a power and a synchronous motor for starting an engine; a reverse power conversion device that is also used as a synchronous motor for starting the engine and starts the synchronous machine by a low-frequency starting method; a storage battery that is also used as a power supply device at the time of starting and at the time of uninterruptible power and is formed of an energy storage body; a bidirectional power conversion device that performs charge and discharge control of the storage battery; and a double-throw type switch that switches between an AC side and a system side of the bidirectional power conversion device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power generating device, and more particularly to an engine-driven power generating device and engine-driven power generating system with an uninterruptible power switching function in which a generator is also used as a starter motor. [Background technology]

[0002] Conventionally, emergency engine-driven generators have been used as standby power sources in social and industrial activities to prepare for unexpected power outages and fluctuations in system voltage and frequency.

[0003] This type of engine-driven generator must be started in the event of a power outage, so it is started using compressed air or a DC starting motor (starter motor), etc. Starting with compressed air can be done by rotating a starting air motor using compressed air stored in a tank, or by directly pushing down the engine piston to start the engine.

[0004] However, compressors that generate compressed air and tanks that store compressed air are subject to relevant laws and regulations, and they require notification and maintenance.

[0005] For this reason, most emergency engine-driven generators, regardless of the type, such as gas turbine engines or diesel reciprocating engines, widely adopt an electric starting method using an easy-to-operate starting motor.

[0006] Generally, a starting motor requires a large torque to start a stopped engine, and a DC motor (cell motor) connected to a storage battery or an inverter-driven squirrel-cage induction motor is used.

[0007] In addition, a separate power source such as an external power supply or a storage battery is required to start the device, and a conversion device such as a rectifier (RF) to charge the storage battery or a forward power conversion device (CONV) is required.

[0008] In particular, gas turbine engines (GT) and large diesel engines (DE) require a large amount of torque to start, and therefore require a large-capacity starting motor and starting battery.

[0009] Engine-driven generators have a large inertial force, and it takes several tens of seconds from start-up to completion and for the generator to start transmitting electricity. Furthermore, in the case of gas reciprocating engines, the start-up time can sometimes be several minutes.

[0010] The power grid connected to these engine-driven generators cannot supply power to the load until the generator starts transmitting power, resulting in a power outage.

[0011] On the other hand, to prepare for power outages and fluctuations in system voltage and frequency, there is a constant voltage constant frequency (CVCF) system that combines a forward converter (CONV) that rectifies power from AC to DC and an inverse converter (INV) that rectifies power from DC to AC. Furthermore, if a storage battery is connected to the common DC part of this system to compensate for power outages, it is called an uninterruptible power supply system (UPS).

[0012] Generally, uninterruptible power supply systems (UPS) provide backup for short-term power outages, while emergency engine-driven generators provide backup for long-term power outages lasting from a few tens of seconds to several hours.In addition, for important loads and equipment that cannot tolerate not only power outages but also momentary power outages of less than one cycle or voltage waveform disturbances, such as the power systems of data centers, both uninterruptible power supplies (UPS) and engine-driven generators are connected together as part of the power supply system. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-196355 Summary of the Invention [Problem to be solved by the invention]

[0014] The problem that the present invention aims to solve is to provide an engine-driven power generating device and an engine-driven power generating system that make it possible to omit the engine starting battery and the starting electric motor, thereby reducing costs and saving space. [Means for solving the problem]

[0015] In order to achieve the above object, the present invention takes the following measures.

[0016] That is, a first aspect of the present invention is an engine-driven power generating system including a synchronous machine that serves both as an AC generator for supplying power and as a synchronous motor for starting the engine, an inverse power conversion device that starts the synchronous machine as a synchronous motor for starting the engine by a low-frequency starting method, a storage battery made of an energy storage device that serves both as a power supply device at startup and during uninterruptible power supply operations, a bidirectional power conversion device that controls charging and discharging of the storage battery, and a double-throw changeover switch that switches between the AC side of the bidirectional power conversion device and the grid side.

[0017] A second aspect of the present invention is the engine-driven power generation system of the first aspect, in which the drive source of the AC generator includes at least one of a gas turbine engine and a gas reciprocating engine as a diesel engine, and the synchronous machine is used as a synchronous motor to start the engine, thereby realizing an uninterruptible power switching function and serving as both an AC generator and a synchronous motor.

[0018] A third aspect of the present invention is the engine-driven power generating device of the first aspect, wherein the energy storage device comprises a secondary battery made of any of a lead-acid battery, a lithium-ion battery, and an all-solid-state battery, or any combination of electric double-layer capacitors (capacitors) capable of charging and discharging electrical energy.

[0019] A fourth aspect of the present invention is the engine-driven power generating apparatus of the first aspect, in which the synchronous machine is a rotating machine that is used both as an AC generator and as a synchronous motor for starting the engine, and the inverse power conversion device is either a thyristor inverter, a cyclone converter, or a combination of a thyristor inverter and a cyclone converter.

[0020] A fifth aspect of the present invention is an engine-driven power generation device of the first aspect, in which the bi-directional power conversion device for the energy storage body includes a power conversion device for charge control and a power conversion device for discharge control as charge and discharge control devices.

[0021] A sixth aspect of the present invention is the engine-driven power generating apparatus of the fifth aspect, in which the power conversion device for charge control is a rectifier, and the power conversion device for discharge control is an inverse power conversion device.

[0022] A seventh aspect of the present invention is an engine-driven power generation system including a plurality of engine-driven power generation devices according to any one of the first to sixth aspects. [Effects of the Invention]

[0023] The engine-driven generator and engine-driven power generation system of the present invention share the functions of engine starting and load power supply compensation, making it possible to omit the engine starting battery and starting motor, thereby reducing costs and saving space, and also making maintenance easier.

[0024] Furthermore, the engine-driven power generating device and engine-driven power generating system of the present invention function as an uninterruptible power supply that combines the functions of both an uninterruptible power supply device and an engine-driven power generating device, making it possible to supply power to a load uninterruptedly even if a continuous power source such as a commercial power source fails. [Brief explanation of the drawings]

[0025] [Figure 1]FIG. 1 is a system diagram for explaining the configuration of an engine-driven power generating device according to an embodiment of the present invention and its normal operation. [Figure 2] FIG. 2 is a system diagram for explaining the configuration of an engine-driven power generating device according to an embodiment of the present invention and its operation at the moment of a power outage. [Figure 3] FIG. 3 is a system diagram for explaining the configuration of the engine-driven power generating device according to the embodiment of the present invention and the motor mode / starting of the prime mover. [Figure 4] FIG. 4 is a system diagram illustrating the configuration of an engine-driven power generating device according to an embodiment of the present invention and operation in the power generating mode / when the generator voltage is established. [Figure 5] FIG. 5 is a system diagram illustrating the configuration of an engine-driven power generating device according to an embodiment of the present invention and its operation when switching between power generation modes / power sources. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc., are not necessarily the same as those in reality. Furthermore, even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In this specification and each drawing, elements similar to those described above with reference to the previous drawings are designated by the same reference numerals, and detailed and redundant explanations will be omitted as appropriate.

[0027] FIG. 1 is a system diagram for explaining the configuration of an engine-driven power generating device according to an embodiment of the present invention and its normal operation.

[0028] An engine-driven power generating apparatus (10) according to an embodiment of the present invention is an engine-driven power generating apparatus used as an emergency power source in preparation for a power outage, and includes a synchronous machine (G / M), an inverse power converter (INV), a storage battery (Batt), a bidirectional power converter (CONV), and a double-throw change-over switch (Thy-SW).

[0029] The synchronous machine (G / M) serves both as an AC generator (G) that supplies power and as an electric motor (M) for starting the engine, and has a damper winding (cage inductor) as part of its structure. The electric motor (M) is excited by an AC exciter (ACEX).

[0030] The inverse power converter (INV) starts the synchronous machine (G / M) as the engine starting synchronous motor (M) by the low frequency starting method.

[0031] The battery (Batt) consists of an energy storage device that serves both as a starting and uninterruptible power supply.

[0032] The bidirectional power converter (CONV) controls the charging and discharging of the storage battery (Batt).

[0033] The double-throw transfer switch (Thy-SW) switches between the AC side and the grid side of the bidirectional power converter (CONV).

[0034] First, the normal operation of the engine-driven generator system (10) will be described.

[0035] 1 shows an example of normal operation in which the engine-driven power generating system (10) according to this embodiment is used as an emergency engine-driven power generator, and includes a diesel engine (DE) and a lithium-ion battery (Batt) as one of the energy storage devices. However, the battery is not limited to a lithium-ion battery, and may be, for example, a lead-acid battery, a secondary battery made of any of solid-state batteries, or any combination of an electric double layer capacitor (capacitor) capable of charging and discharging electrical energy.

[0036] In normal operation, the load power supply (B) is supplied with power from the commercial power supply (A) or the like via a direct line of the engine-driven generator (10) (i.e., by closing the circuit breaker (52S) for the normal system, the operation switch (42S) for the normal system, the power generation selection switch (83G), and the transmission / distribution circuit breaker (52L)), and is connected to the storage battery (Batt) by a bidirectional power converter (CONV) via the selection switch a (83G) and the selection switch b (83C) of the double-throw transfer switch (Thy-SW).

[0037] The bidirectional power converter (CONV) operates in synchronization with the power supply on the side of the selective switch a (83G) of the double-throw transfer switch (Thy-SW), and performs floating charging (C) on the storage battery (Batt).

[0038] Next, the operation of the engine-driven generator system (10) at the moment of a power outage will be described.

[0039] Fig. 2 is a system diagram for explaining the configuration of an engine-driven power generating apparatus according to an embodiment of the present invention and its operation during a power outage. The configuration of the engine-driven power generating apparatus (10) illustrated in Fig. 2 is similar to the configuration of the engine-driven power generating apparatus (10) illustrated in Fig. 1, and therefore a duplicated description will be avoided.

[0040] When a power outage (D) occurs, the engine-driven generator (10) detects the power outage using the undervoltage relay (27S) in the input (UV) of the engine-driven generator (10) and opens the operation switch (42S). The engine-driven generator (10) also detects the power outage and opens the selector switch a (83G) of the double-throw transfer switch (Thy-SW) to perform uninterruptible switching (E). The bidirectional power converter (CONV) commutates the power flow from DC to AC due to a drop in the AC input / output voltage, and discharges the power stored in the storage battery (Batt) (F), thereby continuing to supply power to the load (B). In addition, an AC reactor or the like may be installed on the AC input / output side of the bidirectional power conversion device (CONV) to improve the voltage waveform and suppress cross current between the selective switches a (83G) and b (83C) of the double-throw transfer switch (Thy-SW) when the flow of power is commutated.

[0041] Furthermore, upon detecting a power outage, the engine-driven generator (10) operates a starting inverting power converter (INV) and closes a circuit breaker (52GM) and an operation switch (42G).The engine-driven generator (10) further applies an appropriate low frequency and low voltage to the synchronous machine (G / M) using the starting INV, and performs low-frequency starting using the damper winding (cage inductor) of the synchronous machine (G / M).

[0042] Next, the operation of the engine-driven generator (10) in the motor mode / startup of the prime mover will be described.

[0043] Fig. 3 is a system diagram for explaining the configuration of an engine-driven generator according to an embodiment of the present invention and the motor mode / start of the prime mover. The configuration of the engine-driven generator (10) illustrated in Fig. 3 is similar to the configuration of the engine-driven generator (10) illustrated in Fig. 1, so a duplicated description will be avoided.

[0044] After starting the synchronous machine (G / M), the inverse power converter (INV) for starting accelerates the synchronous machine (G / M) through voltage-frequency proportional (V / F) control, closes the field switch (41G) to perform field control of the synchronous machine (G / M), and operates it as a synchronous motor (M) through the automatic voltage regulator (AVR) in motor mode, bringing it up to synchronous speed.

[0045] Then, the starting inverting power converter (INV) controls the voltage and frequency, and the synchronous machine (G / M) accelerates the diesel engine (DE) to a rotational speed at which it can start itself, and starts the diesel engine (DE) (H).

[0046] Note that the battery discharge (F) and the load power supply (B) are the same as those explained with reference to FIG. 2, so a duplicate explanation will be avoided.

[0047] Next, the operation of the engine-driven generator system (10) in the power generation mode / when the generator voltage is established will be described.

[0048] Fig. 4 is a system diagram illustrating the configuration of an engine-driven power generating apparatus according to an embodiment of the present invention and its operation in a power generating mode / when establishing a voltage of the generator. The configuration of the engine-driven power generating apparatus (10) illustrated in Fig. 4 is similar to the configuration of the engine-driven power generating apparatus (10) illustrated in Fig. 1, and therefore a duplicated description will be avoided.

[0049] After starting the diesel engine (DE), the engine-driven generator (10) further accelerates the diesel engine (DE) and settles it to a specified speed (rated rotation). After settling, the engine-driven generator (10) switches the automatic voltage regulator (AVR) to a power generation mode, operates the synchronous machine (G / M) as a synchronous generator (G), and establishes a voltage (I).

[0050] Note that the battery discharge (F) and the load power supply (B) are the same as those explained with reference to FIG. 2, so a duplicate explanation will be avoided.

[0051] Next, the operation of the engine-driven generator (10) when switching between power generation modes / power sources will be described.

[0052] Fig. 5 is a system diagram illustrating the configuration of an engine-driven power generating apparatus according to an embodiment of the present invention and its operation when switching between power generation modes and power sources. The configuration of the engine-driven power generating apparatus (10) illustrated in Fig. 5 is similar to the configuration of the engine-driven power generating apparatus (10) illustrated in Fig. 1, and therefore a redundant description will be avoided.

[0053] During operation in power generation mode / power supply switching, the engine-driven generator (10) controls the bidirectional power converter (INV) that supplies power to the load using the storage battery (Batt) to synchronize the power supply of the synchronous generator (G). After synchronization is achieved, the selector switch a (83G) of the double-throw transfer switch (Thy-SW) is synchronized. The engine-driven generator (10) then opens the selector switch b (83C) of the double-throw transfer switch or stops the bidirectional power converter (CONV), thereby supplying power to the load from the generator (G) through synchronous uninterruptible transfer (J).

[0054] Furthermore, if there is surplus power in the generator output during load power supply, the bidirectional power converter (CONV) can be put into charge mode again to charge the storage battery (C) in preparation for restart.

[0055] As described above, the engine-driven generator system (10) according to this embodiment includes a generator that doubles as both a double-throw changeover switch for power source switching and an engine starter motor. It also includes a starter battery, a bidirectional power converter for charging and discharging the battery, and an inverse power converter for controlling the generator as a starter motor. This makes it possible to omit the engine starter battery and the starter motor, thereby achieving cost reduction and space savings.

[0056] The engine-driven generator (10) according to this embodiment also functions as a constant voltage, constant frequency (CVCF) system using the bidirectional power converter and the starter reverse power converter, and functions as an uninterruptible power supply (UPS) from power outage to start-up and load power supply using the starter storage battery. Therefore, even if a continuous power source such as a commercial power source fails, power can be supplied to the load without interruption.

[0057] The engine-driven power generating device (10) according to the present embodiment is not limited to being used alone, but may be used in combination with a plurality of other devices as an engine-driven power generating system.

[0058] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0059] 27S Undervoltage Relay (for detecting power outages) 41G···Field switch (for generator field) 42G···Operation switch (for generator operation) 42S··· Operation switch (for normal systems) 52G Circuit Breaker (for Generator) 52GM··· Circuit Breaker (for Generator Systems) 52L Circuit Breaker (for power transmission and distribution) 52S··· circuit breaker (for regular systems) 72B DC circuit breaker (for storage batteries) 83C, 83G···Selective switch (for converter output, power generation) A Commercial power supply ACEX...AC exciter AVR: Automatic voltage regulator (for generator and motor modes) B Load power supply Batt...storage battery (secondary battery) C...Storage battery charging CONV... Power conversion device (bidirectional, for charge / discharge control) CVCF: Constant Voltage Constant Frequency Device D Power outage occurs DE: Diesel engine (for driving generators) E... Uninterrupted switching F... Battery discharge G···AC Generator GE Gas Reciprocating Engine G / M: Synchronous machine (motor / generator) GT...Gas turbine engine H. Prime Mover Start I... Voltage establishment J...Synchronous uninterrupted switching INV... Power converter (reverse direction, for starter motor control) M...Synchronous motor RF... Rectifier Thy-SW...Double-throw changeover switch UPS...Uninterruptible power supply

Claims

1. a synchronous machine that serves both as an AC generator for supplying power and as a synchronous motor for starting the engine; an inverse power conversion device that starts the synchronous machine as a synchronous motor for starting the engine by a low frequency starting method; a storage battery comprising an energy storage body, which is used as a power supply both at startup and during uninterruptible power outages; a bidirectional power conversion device that controls charging and discharging of the storage battery; a double-throw changeover switch that switches between the AC side and the system side of the bidirectional power conversion device; An engine-driven power generating device comprising:

2. the drive source of the AC generator includes at least one of a gas turbine engine and a gas reciprocating engine as a diesel engine, 2. The engine-driven power generating system according to claim 1, wherein the synchronous machine is used as the synchronous motor to start the engine, thereby realizing an uninterruptible power supply switching function and also serving as the AC generator and the synchronous motor.

3. 2. The engine-driven power generating apparatus according to claim 1, wherein the energy storage device comprises a secondary battery selected from the group consisting of a lead-acid battery, a lithium-ion battery, and an all-solid-state battery, or comprises any combination of electric double-layer capacitors capable of charging and discharging electrical energy.

4. the synchronous machine is a rotating machine that serves both as the AC generator and as a synchronous motor for starting an engine, 2. The engine-driven power generating system according to claim 1, wherein the inverse power conversion device is any one of a thyristor inverter, a cyclone converter, or a combination of a thyristor inverter and a cyclone converter.

5. 2. The engine-driven power generating system according to claim 1, wherein the bidirectional power conversion device for the energy storage body includes a power conversion device for charge control and a power conversion device for discharge control as charge and discharge control devices.

6. the power conversion device for charge control is a rectifier, 6. The engine-driven power generating system according to claim 5, wherein the power converter for discharge control is the inverse power converter.

7. An engine-driven power generation system comprising a plurality of engine-driven power generation devices according to any one of claims 1 to 6.

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