JP2011050192A - Engine generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately discriminate a state in which a failure occurs with an engine from a state in which there is misfiring in the engine. <P>SOLUTION: The engine generator includes a generator which is driven by an engine, and an inverter which links the output of the generator to a commercial power system. Misfiring and generator failure determining means 31 and 33 are provided which determine a miss firing state where miss firing occurs with the engine, if a generated power value representing a generated output of the generator is equal to or less than a voltage drop reference value and a drop side change value of the rotational speed representing the change in the rotational speed of the engine to a dropping side is larger than a misfiring occurrence reference value which is a change reference value of the rotational speed; and it is determined that it is in a generator failure state where a failure occurs with the generator, if the generated power value is a voltage drop reference value or lower and the dropping side change value is a misfiring reference value or lower. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an engine power generator including a generator driven by an engine and an inverter that interconnects a power generation output of the generator with a commercial power system.

  In a conventional engine power generation device, for example, a generator having a three-phase output winding is driven by an engine, and a converter that converts AC power output from the generator into DC power is provided. Is converted into AC power that matches the frequency and voltage of the commercial power system, thereby connecting the power generation output of the generator to the commercial power system (see, for example, Patent Document 1). In the apparatus described in Patent Document 1, since it is required to monitor whether or not the generator has failed, the DC voltage from the converter input to the inverter is monitored, and the DC voltage is monitored. When the value drops below the planned value, it is determined that the generator has failed.

Japanese Patent No. 3676660

  In the device described in Patent Document 1, the DC voltage input to the inverter is reduced when the generator is broken, so that the DC voltage of the inverter is reduced to a predetermined value or less. Judged as a failure. However, the cause of the decrease in the DC voltage of the inverter is not only the failure of the generator, but also the DC voltage of the inverter when a temporary misfire occurs in the engine. Therefore, in the apparatus described in Patent Document 1, there is a possibility that it is determined that the generator has failed even when a temporary misfire has occurred in the engine.

  The present invention has been made paying attention to this point, and its purpose is to accurately distinguish between a state in which a generator failure has occurred and a state in which a temporary misfire has occurred in the engine. It is in the point which provides the engine electric power generator which can do.

In order to achieve this object, a characteristic configuration of an engine power generator according to the present invention is an engine including a generator driven by the engine, and an inverter that interconnects the power generation output of the generator with a commercial power system. In the power generator,
Misfire caused when the generated power value indicating the power generation output of the generator is equal to or lower than the voltage decrease reference value and the rotation speed decrease side change value indicating the change to the engine rotation speed decrease side is the rotation speed change reference value If it is greater than the generation reference value, it is determined that the engine misfire has occurred, and the generated power value is equal to or lower than the voltage drop reference value, and the lower side change value is the misfire occurrence. When it is below the reference value, it is provided with misfire / generator failure determination means for determining that the generator is in a generator failure occurrence state.

  When an engine misfire occurs, the generated power value decreases, and the rotational speed of the engine also changes to the lower side. On the other hand, when the generator fails, the generated power value decreases, but the engine speed does not change to the lower side. Therefore, according to this characteristic configuration, the misfire / generator failure determination means does not simply use the generated power value indicating the power generation output of the generator, but in addition to the generated power value, the engine speed decreases. If the generated power value is below the voltage drop reference value and the drop change value is greater than the misfire occurrence reference value, the engine speed actually decreases. Assuming that it is in a misfire occurrence state, if the generated power value is less than the voltage drop reference value and the lower side change value is less than the misfire occurrence reference value, the engine speed is not reduced, It is determined that a generator failure has occurred. Therefore, whether or not the engine speed has actually decreased is not only by comparing the generated power value with the voltage drop reference value but also by comparing the decrease side change value with the misfire occurrence reference value. Therefore, it is possible to accurately distinguish whether it is a misfire occurrence state or a generator failure occurrence state. Moreover, although engine misfire occurs instantaneously, the change value on the lower side of the rotational speed indicates the change to the lower side of the engine speed. The value is accurately reflected. Therefore, the misfire occurrence state can be accurately determined by comparing the lower side change value and the misfire occurrence reference value.

  From the above, when a temporary misfire has occurred in the engine, it can be accurately determined that a misfire has occurred, but when a generator failure has occurred, It is possible to accurately determine the state in which a generator failure has occurred and the state in which a temporary misfire has occurred in the engine, and a temporary misfire has occurred in the engine. It is possible to realize an engine power generator that does not make a false determination that the generator has failed.

  According to a further characteristic configuration of the engine power generator according to the present invention, when the rotational speed of the engine or a rotational speed value indicating a change in the rotational speed is equal to or lower than a low rotational reference value, the rotational speed of the engine is abnormally decreased. The low rotation abnormality determining means for determining the low rotation abnormality state is provided.

  According to this characteristic configuration, the low rotation abnormality determining means determines that the engine is in a low rotation abnormality state if the rotation speed value of the engine or the rotation speed value indicating the change in the rotation speed is equal to or lower than the low rotation reference value. A state in which a failure has occurred can be determined. Then, after determining the low-rotation abnormality state by the low-rotation abnormality determination unit, as described above, the misfire occurrence state and the generator failure occurrence state are determined by the misfire / generator failure determination unit. While it is possible to accurately determine engine failure including misfire, it is possible to accurately distinguish and determine engine failure including misfire and generator failure.

  According to a further characteristic configuration of the engine power generation device according to the present invention, the misfire / generator failure determination means may change, as the decrease side change value, a change to the decrease side of the rotation speed of the engine during a first calculation time. The low rotation abnormality determining means obtains a value indicating a change in the rotation speed of the engine during a second calculation time as the rotation speed value, and the first calculation time is The time is set shorter than the second calculation time.

  According to this feature configuration, both the lower-side change value and the rotation speed value are values for changes in the engine rotation speed, but the first calculation time is set to be shorter than the second calculation time. The lower side change value can be repeatedly determined in a shorter time than the rotation speed value. Thereby, the determination of the misfire / generator failure determination means can be repeatedly performed in a shorter time than the determination of the low rotation abnormality determination means. Therefore, basically, it is possible to determine the engine failure by the determination of the low rotation abnormality determination means, but it is possible to accurately determine the engine failure due to the instantaneous misfire by the determination of the misfire / generator failure determination means. The engine failure can be determined with higher accuracy.

  According to a further characteristic configuration of the engine power generator according to the present invention, the misfire / generator failure determining means sets, as the generated power value, a value indicating a change in the generated power output of the generator during the first calculation time. There is in point to ask.

  According to this feature configuration, the misfire / generator failure determination means obtains not only the lower side change value but also the generated power value during the first calculation time, so the lower side change value at the same timing. And the misfire occurrence state and the generator failure occurrence state can be determined using the generated power value. Therefore, the misfire occurrence state and the generator failure occurrence state can be more accurately distinguished.

  A further characteristic configuration of the engine power generation device according to the present invention is provided with a rotation speed adjusting means for adjusting the rotation speed of the engine to a target rotation speed, and the misfire occurrence reference value and the low rotation reference value are the engine target values. The configuration is such that the value can be changed and set according to the rotational speed.

  According to this feature configuration, since the rotation speed adjusting means adjusts the engine rotation speed to the target rotation speed, the engine rotation speed can be changed by changing and setting the target rotation speed. The power generation output of the generator can be changed with the change in speed. Therefore, for example, the power generation output of the generator can be changed according to the required power amount at the power load, and the power generation output of the generator can be changed as necessary. Since the misfire occurrence reference value and the low rotation reference value are changed and set to values corresponding to the target engine speed, the misfire occurrence state and the generator failure occur in a state appropriately corresponding to the changed target engine speed. The state can be determined.

Diagram showing schematic configuration of cogeneration system Block diagram of the operation control unit for explaining how to obtain the decrease side change value, the generated power value, and the rotation speed value Flow chart showing operation for determining misfire occurrence state and generator failure occurrence state Flow chart showing operation for determining low rotation abnormal state

An embodiment of a cogeneration system to which an engine power generator according to the present invention is adapted will be described with reference to the drawings.
As shown in FIG. 1, this cogeneration system recovers exhaust heat generated in the engine 1 and the engine generator 3 according to the present invention configured to drive the generator 2 by the engine 1 and stores hot water. An exhaust heat recovery unit 6 that stores hot water in the tank 4 and supplies a heat medium to the heat consuming terminal 5 and an operation control unit 7 that controls the operation of the cogeneration system are provided.

  The engine power generator 3 is connected to the output shaft of the engine 1 and generates AC power by driving the engine 1 (permanent magnet type 20-pole three-phase AC generator), and AC output from the generator 2. The converter 8 which converts electric power into direct-current power, and the inverter 9 which converts the direct-current power output from the converter 8 into alternating current power are provided. The commercial power system 10 is electrically connected to a power load 12 such as a television, a refrigerator, or a washing machine via a power supply line 11. The inverter 9 links the power output of the generator 2 to the commercial power system 10 by converting the DC power from the converter 8 into AC power that matches the frequency and voltage of the commercial power system 10.

  The inverter 9 is electrically connected to the power supply line 11 via the cogeneration power supply line 13, and is configured to be able to supply the generated power from the generator 2 to the power load 12. Although not shown, the power supply line 11 is provided with power load measuring means for measuring the load power of the power load 12, and this power load measuring means generates a reverse power flow in the current flowing through the power supply line 11. It is configured to detect whether or not. And the electric power supplied to the electric power supply line 11 from the generator 2 is controlled by the inverter 9 so that a reverse power flow does not occur, and the surplus electric power of the generated electric power is converted into the electric heater H that can convert the surplus electric power into heat. It is configured to be supplied.

  The electric heater H is provided so as to freely heat the engine coolant flowing through the coolant circuit 14. The coolant circuit 14 circulates the engine coolant between the engine 1 and the exhaust heat recovery heat exchanger 16 by the operation of the coolant pump 15. The electric heater H is configured such that the heating amount of the engine cooling water can be adjusted according to the amount of surplus power so that the power consumption increases and the heating amount of the engine cooling water increases as the amount of surplus power increases. Has been.

  The operation of the engine 1 is controlled by the operation control unit 7. Although not shown, the engine 1 has a configuration similar to that of a normal four-cycle engine. After an air-fuel mixture of fuel gas (for example, natural gas) and air is sucked into the combustion chamber, the air-fuel mixture is mixed in the combustion chamber. After that, the air-fuel mixture is ignited and expanded in the combustion chamber, and the exhaust gas generated by the combustion is exhausted to the exhaust passage. The piston of the engine 1 is swingably connected to the connecting rod, and the reciprocating motion of the piston is converted into the rotational motion of the crankshaft by the connecting rod. The engine 1 is provided with a rotation sensor 17 capable of detecting the engine rotation speed by detecting the angle of the crankshaft. The rotation sensor 17 is configured to output one pulse when the crankshaft makes one rotation. Yes.

  The exhaust heat recovery unit 6 passes through a hot water storage tank 4 for storing hot water in a state where temperature stratification is formed, a hot water circulation pump 19 for circulating hot water in the hot water storage tank 4 through the hot water passage channel 18, and a hot water passage channel 18. Exhaust heat recovery heat exchanger 16 that heats flowing hot water, an auxiliary heating heat exchanger 22 that heats hot water flowing through the hot water flow path 18 by combustion of the burner 21 with the fan 20 activated, etc. It has. A take-out passage 23 that communicates with the hot water passage 18 and the lower portion of the hot water storage tank 4 and a hot water passage 24 that communicates with the hot water passage 18 and the upper portion of the hot water storage tank 4 are provided. Is provided. Further, the hot water storage path 24 is configured to supply hot water by supplying hot water taken out from the upper part of the hot water storage tank 4 or hot water passing through the auxiliary heating heat exchanger 22 to a hot water tap or the like.

  By the operation of the hot water circulation pump 19, hot water taken out from the lower portion of the hot water storage tank 4 by the take-out passage 23 is supplied to the heat exchanger 16 for exhaust heat recovery through the hot water passage 18. In the heat exchanger 16 for exhaust heat recovery, heat is exchanged between the engine cooling water of the cooling water circuit 14 having the exhaust heat of the engine 1 and the hot water in the hot water passage 18 to heat the hot water with the engine cooling water. It is configured as follows. Then, by opening the hot water storage valve 25, the hot water passing through the exhaust heat recovery heat exchanger 16 can be returned to the upper part of the hot water storage tank 4, and hot water is supplied to the hot water storage tank 4 by the exhaust heat of the engine 1. It is configured to be able to store hot water.

  The heat consumption passage 26 connected to the hot water passage 18 is provided with an intermittent valve 27 for intermittently passing the hot water and a heat exchanger 28 for heat medium heating. A heat medium circulation pump 30 that circulates the heat medium between the heat medium heating heat exchanger 28 and the heat consuming terminal 5 through the heat medium circulation path 29 is provided. Thereby, in the heat exchanger 28 for heat medium heating, the hot water heated by the heat exchanger 16 for exhaust heat recovery or the heat exchanger 22 for auxiliary heating is caused to flow, so that the heat medium circulation path 29 is passed. The flowing heat medium is configured to be heated. The heat consuming terminal 5 is composed of a heating terminal such as a floor heating device or a bathroom heating device.

  The operation control unit 7 is configured to control the operation of the engine 1 and the like by executing a predetermined computer program. For example, with respect to the required power amount at the power load 12 and the required heat amount at the heat consuming terminal 5 or the hot water supply, the operation control unit 7 determines the future required power amount and the required demand based on the past required power amount and the past required heat amount. The amount of heat is configured to be predictable. Then, the operation control unit 7 operates the engine 1 according to the predicted future required power amount or required heat amount in order to cover the required power amount at the power load 12 or the required heat amount at the heat consuming terminal 5 or the hot water supply. Configured to control. When operating the engine 1, the operation control unit 7 operates the cooling water pump 15 and the hot water circulation pump 19, recovers the exhaust heat of the engine 1 with hot water in the hot water passage 18, and stores it in the hot water storage tank 4. It is configured to store hot water.

  As described above, the operation control unit 7 determines the engine 1 according to the predicted future required power amount or required heat amount in order to cover the required power amount at the power load 12 or the required heat amount at the heat consuming terminal 5 or the hot water supply. The operation is controlled. For example, when the so-called main heat operation is performed in which the operation of the engine 1 is controlled according to the predicted required heat amount in order to cover the required heat amount in the heat consuming terminal 5 or the hot water supply, etc. Surplus power that is a surplus with respect to the power load 12 of the generated power of the machine 2 is generated. At this time, surplus power is supplied to the electric heater H by the inverter 9. Thereby, the electric heater H will heat the engine cooling water of the cooling water circuit 14 with the surplus power, and in addition to recovering the exhaust heat of the engine 1, the surplus power is converted into heat and converted. The heat can also be collected.

  In the engine power generation device 3 according to the present invention, as shown in FIG. 2, in order to distinguish and determine the state in which the failure of the generator 2 has occurred and the state in which the engine 1 has misfired, The operation control unit 7 includes a generator failure determination unit 31 and a calculation unit 33 that performs various calculations. In the engine power generation device 3 according to the present invention, the operation control unit 7 operates the engine 1 at a rated rotational speed (for example, 1200 rpm), and the generator 1 is driven by driving the engine 1 at the rated rotational speed. It is comprised so that the generated electric power may be output.

  The operation control unit 7 measures the AC voltage V2 from the generator 1 every time the first calculation cycle (for example, 0.5 ms (2 kHz)) elapses, and the measured AC voltage V2 is supplied to the calculation unit 33. Have been entered. The calculating part 33 is calculating | requiring the rotational speed of the engine 1 from the frequency of the input alternating voltage V2. For example, when the generator 2 is a permanent magnet type 20-pole three-phase AC generator, if the frequency of the AC voltage V2 is 200 Hz, the rotational speed of the engine 1 is determined to be 1200 rpm. Then, the calculation unit 33 calculates a moving average value of the rotation speed of the engine 1 during a first calculation time (for example, 100 ms), and calculates a difference between the moving average value obtained last time and the moving average value calculated this time as the rotation speed. The lower side change value N1 is output to the misfire / generator failure determination unit 31. The decrease side change value N1 of the rotation speed indicates a change to the decrease side of the rotation speed of the engine 1, and is a difference in the moving average value of the rotation speed of the engine 1 during the first calculation time. As for the method of obtaining the moving average value, the average value of the rotation speed of the engine 1 obtained every first calculation period (for example, 0.5 ms) between the current time and the first calculation time (for example, 100 ms) is used. The next moving average value is obtained every time one calculation cycle (for example, 0.5 ms) elapses and the rotation speed of the next engine 1 is obtained.

  The operation control unit 7 measures the DC voltage V3 input from the converter 8 to the inverter 9 every time the first calculation cycle (for example, 0.5 ms (2 kHz)) elapses, and uses the measured DC voltage V3. This is input to the calculation unit 33. The calculation unit 33 calculates a moving average value of the DC voltage V3 during the first calculation time (for example, 100 ms), and outputs the calculated moving average value to the misfire / generator failure determination unit 31 as the generated power value V1. Yes. The generated power value V1 indicates the power generation output of the generator 2, and is a moving average value of the DC voltage V3 during the first calculation time. About the method of calculating | requiring a moving average value, it calculates | requires similarly to the moving average value of the rotational speed of the engine 1 mentioned above.

  Accordingly, the misfire / generator failure determination unit 31 includes a decrease side change value N1 calculated by the calculation unit 33 (difference in moving average value of the rotation speed of the engine 1 during the first calculation time) and generated power. A value V1 (moving average value of the DC voltage V3 during the first calculation time) is input. The misfire / generator failure determination unit 31 has misfired the engine 1 when the generated power value V1 is equal to or lower than the voltage drop reference value Va and the lower side change value N1 is greater than the misfire occurrence reference value Na. It is determined that a misfire has occurred. Further, the misfire / generator failure determination unit 31 causes the generator 1 to fail when the generated power value V1 is equal to or lower than the voltage drop reference value Va and the decrease side change value N1 is equal to or less than the misfire occurrence reference value Na. It is determined that the generator has failed. Therefore, the misfire / generator failure determination means includes the misfire / generator failure determination unit 31 and the calculation unit 33. Here, the voltage drop reference value Va is set to 300 V, for example, and can be set to a value at which output of AC 200 V is disabled. The misfire occurrence reference value Na is a change reference value of the rotational speed of the engine 1, and is, for example, a target rotational speed of the engine 1 × 0.1. Since the engine 1 uses a rated rotational speed (for example, 1200 rpm) as a target rotational speed, the misfire occurrence reference value Na is set to 120 rpm.

Hereinafter, determination of the misfire occurrence state and the generator failure occurrence state will be described based on the flowchart of FIG.
After starting the operation of the engine 1, the operation control unit 7 starts the power generation by the generator 2 and continues the power generation by the generator 2 (steps # 1 and # 2). The misfire / generator failure determination unit 31 receives the generated power value V1 calculated by the calculation unit 33, and the calculation unit 33 calculates that the generated power value V1 is equal to or lower than the voltage drop reference value Va. It is determined whether or not the decreased side change value N1 is larger than the misfire occurrence reference value Na (steps # 3 and 4). The misfire / generator failure determination unit 31 determines that the misfire occurrence state is present when the decrease side change value N1 is greater than the misfire occurrence reference value Na, and determines the misfire occurrence state for a set time (for example, 30 minutes). If it is performed more than the set number of times (for example, 5 times), it is determined that there is a misfire failure of the engine 1, and the operation of the engine 1 is stopped (steps # 5 to # 8). In step # 4, the misfire / generator failure determination unit 31 determines that the generator failure has occurred when the decrease side change value N1 is equal to or less than the misfire occurrence reference value Na. If the determination continues for a set time (for example, 1 second) or longer, the operation of the engine 1 is stopped (steps # 9 to # 11, step # 8), assuming that the generator 2 has failed. The misfire / generator failure determination unit 31 repeats the operations of steps # 3 and 4 every time the generated power value V1 calculated by the calculation unit 33 and the decrease side change value N1 are input. .

  In this way, the calculation unit 33 obtains the rotation speed decrease side change value N1 and the generated power value V1 in the first calculation time (for example, 100 ms), and the misfire / generator failure determination unit 31 Based on the decrease side change value N1 and the generated power value V1, the misfire occurrence state and the generator failure occurrence state can be distinguished and determined. Further, the misfire / generator failure determination unit 31 outputs the decrease side change value N1 and the generated power value V1 from the calculation unit 33 every time the first calculation cycle (for example, 0.5 ms) elapses. And the generator failure occurrence state can be repeatedly performed in a short time. Therefore, in the present invention, it is possible to quickly and accurately determine the misfire occurrence state and the generator failure occurrence state. Further, the rotational speed of the engine 1 when the rotational speed decrease side change value N1 is obtained is not determined by using the output information of the rotation sensor 17 but by the frequency of the AC voltage V2 from the generator 1, thereby instantaneously. It is possible to accurately determine the misfire occurrence state of misfire occurring in Further, since both the lower side change value N1 and the generated power value V1 are values in the first calculation time, it can be determined using the lower side change value N1 and the generated power value V1 at the same timing, and the misfire occurrence state And the generator failure occurrence state can be more accurately distinguished.

As shown in FIG. 2, in addition to the misfire / generator failure determination unit 31, the operation control unit 7 includes a low rotation abnormality determination unit that determines a low rotation abnormality state in which the rotation speed of the engine 1 is abnormally decreased. 32 is provided.
The operation control unit 7 measures the output information P of the rotation sensor 17 (one pulse output for each rotation of the crankshaft), and inputs the measured output information P of the rotation sensor 17 to the calculation unit 33. ing. The calculation unit 33 calculates a moving average value of the rotation speed of the engine 1 during the second calculation time (for example, 500 ms), and sets the calculated moving average value as the rotation speed value N2 to the low rotation abnormality determination unit 32. Output. The rotational speed value N2 indicates the rotational speed of the engine 1, and is a moving average value of the rotational speed of the engine 1 during the second calculation time. When the rotational speed value N2 input from the computing unit 33 is equal to or lower than the low rotational reference value Nb, the low rotational speed abnormality determining unit 32 determines that the rotational speed of the engine 1 is abnormally low. Therefore, the low-rotation abnormality determining means includes a low-rotation abnormality determining unit 32 and a calculation unit 33. For the low rotation reference value Nb, for example, the target rotation speed of the engine 1 is set to 0.8. Since the engine 1 has a rated rotation speed (for example, 1200 rpm) as the target rotation speed, the low rotation reference value Nb is set to 960 rpm. It is set.

Hereinafter, determination of the low rotation abnormality state will be described based on the flowchart of FIG.
The operation control unit 7 monitors the rotation speed of the engine 1 based on the output information of the rotation sensor 17 after starting the operation of the engine 1. The low rotation abnormality determination unit 32 determines that the low rotation abnormality state is present when the rotation speed value N2 calculated by the calculation unit 33 is input and the rotation speed value N2 is equal to or less than the low rotation reference value Nb. Then, the operation of the engine 1 is stopped (steps # 12 to 14). If the rotation speed value N2 is greater than the low rotation reference value Nb, the operation control unit 7 continues the operation of the engine 1 (step # 15).

  The operation shown in the flowchart of FIG. 3 and the operation shown in the flowchart of FIG. 4 are performed in parallel, and the misfire / generator failure determination unit 31 is obtained in the first calculation time (for example, 100 ms). Based on the lower side change value N1 and the generated power value V1, the misfire occurrence state and the generator failure occurrence state are distinguished and determined, and the low rotation abnormality determination unit 32 performs the rotation in the second calculation time (for example, 500 ms). Based on the speed value N2, the low rotation abnormality state is determined. The first calculation time is set to be shorter than the second calculation time, and the determination of the misfire occurrence state and the generator failure occurrence state is repeatedly performed in a shorter time than the determination of the low rotation abnormality state. Here, for example, when the rotational speed of the engine 1 is 1200 rpm, 100 ms that is the first calculation time for obtaining the decrease side change value N1 and the generated power value V1 corresponds to one cycle, and the rotational speed value N2 500 ms, which is the second calculation time when obtaining the value, corresponds to 5 cycles.

  Accordingly, in the present invention, the engine system failure is basically determined by determining the low-rotation abnormality state in which the rotational speed of the engine 1 is decreasing due to a failure in the engine system by the low-rotation abnormality determination unit 32. Furthermore, misfire that occurs instantaneously by the misfire / generator failure determination unit 31 distinguishing and determining the misfire occurrence state and the generator failure occurrence state in a shorter time than determining the low rotation abnormality state When an engine system failure occurs, it is possible to accurately distinguish between an engine system failure and an electrical system failure such as a generator without erroneously determining that it is a failure of an electrical system such as a generator. Can be determined.

[Another embodiment]
(1) In the above embodiment, the difference between the moving average values obtained by subtracting the moving average value obtained this time from the moving average value obtained last time after obtaining the moving average value of the rotational speed of the engine 1 during the first calculation time. Is the decrease side change value N1, for example, the rate of change of the rotational speed of the engine 1 per unit time to the decrease side can also be set as the decrease side change value N1, and in this case, the unit time is calculated as the first calculation. It can be time.

(2) In the above embodiment, the DC voltage V3 input to the inverter 9 is used to determine the generated power value V1. For example, the generated power value V1 using the AC voltage V2 output from the generator 2 is used. Can also be requested.

(3) In the above embodiment, the moving average value of the rotation speed of the engine 1 during the second calculation time (for example, 500 ms) is the rotation speed value N2, but the average rotation of the engine 1 per unit time The speed can also be set to the rotation speed value N2, and in this case, the unit time can be set as the second calculation time. Alternatively, the rotational speed of the engine 1 can be simply set to the rotational speed value N2.

(4) In the above embodiment, the engine 1 is operated at a rated rotational speed (for example, 1200 rpm). For example, the operation control unit 7 responds to the required power amount at the power load 12. Thus, the higher the required power amount, the higher the target rotational speed can be set, and the rotational speed of the engine 1 can be controlled so as to be the set target rotational speed. As described above, the operation control unit 7 controls the rotation speed of the engine 1 so that the operation control unit 7 corresponds to the rotation speed adjusting means. In this case, the operation control unit 7 changes and sets the misfire occurrence reference value Na and the low rotation reference value Nb to values according to the target rotation speed of the engine 1. Here, the misfire occurrence reference value Na can be set, for example, as the target rotation speed of the engine 1 × 0.1 as described above, and the low rotation reference value Nb is also set as the target rotation of the engine 1 as described above. Speed can be set to 0.8.

  The present invention includes a generator driven by an engine and an inverter that interconnects the power generation output of the generator to a commercial power system, and a state where a malfunction of the generator has occurred and a temporary misfire in the engine Therefore, the present invention can be applied to various types of engine power generators that can accurately distinguish and determine the state in which the engine is generated.

DESCRIPTION OF SYMBOLS 1 Engine 2 Generator 3 Engine power generator 9 Inverter 10 Commercial electric power system 31 Misfire / generator failure determination part (misfire / generator failure determination means)
32 Low rotation abnormality determination unit (low rotation abnormality determination means)
33 arithmetic unit (misfire / generator failure determination means and low rotation abnormality determination means)
N1 Rotational speed decrease side change value N2 Rotational speed value Na Misfire occurrence reference value Nb Low rotation reference value V1 Generated power value Va Voltage decrease reference value

Claims (5)

In an engine power generator comprising a generator driven by an engine and an inverter that interconnects the power generation output of the generator to a commercial power system,
Misfire caused when the generated power value indicating the power generation output of the generator is equal to or lower than the voltage decrease reference value and the rotation speed decrease side change value indicating the change to the engine rotation speed decrease side is the rotation speed change reference value If it is greater than the generation reference value, it is determined that the engine misfire has occurred, and the generated power value is equal to or lower than the voltage drop reference value, and the lower side change value is the misfire occurrence. An engine power generation device comprising misfire / generator failure determination means for determining that a generator failure has occurred in a state where the generator failure has occurred when the value is below a reference value.   Low rotation abnormality determining means for determining that the rotation speed of the engine is abnormally low when the rotation speed value indicating the rotation speed of the engine or a change in the rotation speed is equal to or less than a low rotation reference value. The engine power generator according to claim 1 provided with.   The misfire / generator failure determination means obtains a value indicating a change to a decrease side of the rotation speed of the engine during the first calculation time as the decrease side change value, and the low rotation abnormality determination means A value indicating a change in the rotation speed of the engine during a second calculation time is obtained as the rotation speed value, and the first calculation time is set to be shorter than the second calculation time. Item 3. The engine power generator according to Item 2.   The engine power generator according to claim 3, wherein the misfire / generator failure determination means obtains a value indicating a change in power generation output of the generator during the first calculation time as the generated power value.   Rotational speed adjustment means for adjusting the rotational speed of the engine to a target rotational speed is provided, and the misfire occurrence reference value and the low rotational reference value are configured to be freely changeable to values corresponding to the target rotational speed of the engine. The engine power generator according to any one of claims 2 to 4.

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