JP5475267B2 - Engine generator - Google Patents

Description

  The present invention relates to the technology of an engine generator. More specifically, the present invention relates to a technique for stabilizing the power supply of the engine generator.

In a conventional engine generator, in order to obtain AC power of a predetermined frequency, it is necessary to maintain a constant engine speed regardless of the load, and the fuel consumption is reduced when a relatively small load is applied. Many were uneconomical. In addition, for example, when a motor is connected as an electric device to be used, since the inrush current at the time of starting the motor is particularly large, the electric power generation capacity that can supply this current cannot be started. In order to supply stable power even when the load fluctuates due to the operation, it is necessary to select an engine generator having a sufficient power generation capacity. For this reason, an engine generator with an inverter that can be converted into AC power having a predetermined frequency regardless of the engine speed is often used today, and the control target for the load is to be changed in order to change the engine output according to the size of the load. Is the engine speed or fuel supply amount.
JP 2001-45799 A

  However, in the prior art, the engine speed changes according to the load fluctuation, so that the driving feeling is uncomfortable, and the engine speed due to the response delay of the speed governor and the fuel injection pump when the load suddenly increases. In some cases, stable power generation could not be secured against the decline.

  Therefore, the present invention provides an engine generator capable of realizing a good driving feeling and a stable power supply even when the load suddenly increases in an engine generator with an inverter that secures generated power by changing the engine speed. The purpose is to provide.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  In claim 1, an engine, a generator that is driven by the engine to generate electric power, an inverter device that converts the electric power generated by the generator into AC power of a predetermined frequency, and an engine map based on the engine map In an engine generator having a control device that controls the operating state, an output rate that is a ratio of a generated power difference before and after a load change to a generated power before a load change is calculated, the output rate is compared with a threshold, When the output rate is larger than the threshold value, the electric engine connected to the engine generator is set to the target engine speed corresponding to the generated electric power required, and the target engine speed is stable to the electric equipment. This is called from the engine map created in consideration of the fuel consumption rate and noise level of the engine so that electric power can be supplied.

According to a second aspect of the present invention, an engine, a generator that is driven by the engine to generate electric power, an inverter device that converts the electric power generated by the generator into AC power having a predetermined frequency, and an engine map based on the engine map In an engine generator having a control device for controlling the operating state, the difference between the generated power before and after the load change with respect to the generated power before the load change with the actual engine speed set at the engine speed at the rated operation The output rate is calculated as a ratio of the output rate, and the output rate is compared with a threshold value. When the output rate is greater than the threshold value, the actual engine speed is set to a target engine speed greater than the engine speed during rated operation. Settling .

  According to a third aspect of the present invention, an engine, a generator that is driven by the engine to generate electric power, an inverter device that converts the electric power generated by the generator into AC power having a predetermined frequency, and an engine map based on the engine map In an engine generator having a control device for controlling an operating state, an output rate that is a ratio of a decrease in generated power at the time of a decrease in engine speed due to a load change to a generated power before a load change is calculated, and the output rate is calculated as When the output rate is larger than the threshold value, the engine output determined by the engine load and the engine speed is increased to increase the engine speed to a predetermined value, and recovery of stable generated power is ensured. Therefore, in order to shorten the settling time to the predetermined engine speed, it is created by specifying the engine output increase amount considering the exhaust gas characteristics The, from the engine map, calls the target engine output, until the target engine output is intended to increase the engine output.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, when the load fluctuation applied to the engine is relatively small, the engine speed does not change. Therefore, a good driving feeling is ensured, and the load fluctuation is relatively large. Stable power supply can be realized by increasing the power generation output by increasing the engine speed.

  According to the second aspect of the present invention, since the engine speed increases only when an arbitrarily set threshold value is exceeded, the user can grasp that the load fluctuation applied to the engine is a predetermined value or more. Safety can be ensured by avoiding stopping of electrical equipment due to engine stoppage or power generation capacity shortage.

  According to the third aspect of the present invention, it is possible to shorten the settling time of the engine by speeding up the recovery and increase from the decrease in the engine speed due to the load fluctuation, thereby realizing a stable power supply.

  First, the configuration of the engine generator 1 according to the first embodiment of the present invention will be described.

  As shown in FIG. 1, the engine generator 1 mainly includes an engine 10, a generator 20, an inverter device 30, and an engine side control device 50.

  The engine 10 is a power source that drives the generator 20, and a diesel engine that has high durability and low fuel consumption is employed. The speed control device 11 provided in the engine 10 has a role of controlling the fuel injection pump 12 that supplies the fuel to the engine 10 by mechanically or electrically detecting the engine speed N of the engine 10.

  For example, in the speed governor 11 that mechanically detects a change in the engine speed N, a governor weight is provided on a drive shaft (not shown) that is provided inside the speed governor 11 and is interlocked and rotated by the engine 10. (Not shown) is provided, and at the time of steady operation, the centrifugal force due to the rotation of the governor weight and the biasing force of a governor spring (not shown) that biases the governor weight to keep it in place are balanced. Is in a state.

  Here, when the load on the engine 10 increases and the engine speed N decreases, the urging force of the governor spring overcomes the centrifugal force to adjust the fuel supply amount of the fuel injection pump 12 (not shown). ) To increase the amount of fuel supplied to the engine 10. Further, when the load applied to the engine 10 is removed and the engine speed N increases, the centrifugal force overcomes the urging force of the governor spring, and the fuel supplied to the engine 10 is reduced by interlocking the lever. become.

  As a result, the engine 10 is configured to maintain a constant engine speed N before and after a load change unless there is an instruction from an engine-side control device 50 described later.

  The step motor 11a sets the engine speed N by operating the speed governor 11 in response to an instruction from the engine-side control device 50.

  The stop actuator 11b stops the drive of the engine 10, and is driven by the stop relay 11c.

  The engine state detection means 13 detects the engine speed N, the temperature of the lubricating oil of the engine 10, and the temperature of the cooling water of the engine 10, and is composed of a plurality of sensors such as a speed sensor and a temperature sensor. The

  The generator 20 is a power generator that is driven by the engine 10 to generate power. The generator 20 is mainly composed of a stator and a rotor provided rotatably inside the stator. In general, the generator includes a rotating electric type in which an electromotive force is generated in the rotor and a rotating field type in which an electromotive force is generated in the stator. However, the configuration is not limited in the present invention.

  The inverter device 30 is a device that rectifies the power generated by the generator 20 and then converts the power into AC power having a predetermined frequency and supplies the AC power to an electrical device. The inverter device 30 mainly includes an inverter 31, an inverter-side control device 32, and a communication device 33.

  The inverter 31 includes a converter circuit that converts AC power into DC power, a smoothing capacitor that smoothes the DC power converted by the converter circuit, and DC power that has been smoothed by the smoothing capacitor at a predetermined frequency. And an inverter circuit for converting into AC power. The inverter 31 includes a power element temperature detection unit 31a, an output power detection unit 31b, and the like.

  The power element temperature detecting means 31 a detects the temperature of the power element (switching element) provided in the inverter circuit of the inverter 31.

  The output power detection means 31b detects the power output from the inverter 31.

  The inverter-side control device 32 controls the operation of the inverter 31 (particularly the inverter circuit) based on various data and programs. The inverter-side control device 32 is connected to the inverter 31, the power element temperature detection means 31a, the output power detection means 31b, and the communication device 33, respectively, and the temperature output control unit 32a, the engine map 32b, the generator output determination unit 32c, etc. It comprises.

  The temperature output control unit 32a controls the output power of the inverter 31 based on the temperature of the power element and the like.

  The engine map 32b is various control maps for optimizing the operation of the engine 10. Specifically, it is a correlation map between the generated power P and the engine speed N, engine output increase data for settling assistance when the load fluctuates, and the like.

  The generator output determination unit 32c determines an optimal engine operating state from the output power of the inverter 31 detected by the output power detection means 31b and the engine map 32b.

  The communication device 33 enables data transmission / reception between the inverter device 30 and other devices by CAN communication.

  The display board 40 enables input of various data to the engine generator 1 from the outside, and displays information related to the operating state of the engine generator 1 and the like. The display substrate 40 includes a key switch 41 and the like.

  The key switch 41 is for the operator to start the engine generator 1.

  The engine-side control device 50 is one embodiment of the control device according to the present invention. The engine-side control device 50 can control the operations of the step motor 11a, the stop relay 11c, and the cell motor overrun prevention relay 52. In addition, various data is transmitted to and received from the communication device 33 and the display substrate 40.

  The outside air temperature detecting means 51 detects the outside air temperature of the engine generator 1.

  The cell motor overrun prevention relay 52 switches whether or not current is supplied to the cell motor 53 in order to prevent the cell motor 53 from continuing to rotate even after the engine 10 is started.

  When receiving a signal to start the engine 10, the engine-side control device 50 transmits a signal for driving the cell motor 53 via the cell motor overrun prevention relay 52 to start the cell motor 53. When the engine 10 is started, the cell motor overrun prevention relay 52 is turned off and the operation of the cell motor 53 is stopped.

Here, the control flow of the engine generator 1 according to the first embodiment is shown in FIG. 2, the relationship between the generated power P and the engine speed N is shown in FIG. 3, and the relationship between the engine speed N and the output rate Pr (%). Is shown in FIG. The output rate Pr (%) is a ratio of the difference (P2−P1) between the generated power P2 after the load change and the generated power P1 before the load change with respect to the generated power P1 before the load change. . Pr (%) = | {(P2-P1) / P1} × 100 |
The generated power Ps and the engine speed Ns represent values when the engine 10 is rated.

  As shown in FIG. 3, it is assumed that the engine 10 is operated at the engine speed N1 in order to obtain the generated electric power P1 required by the electric equipment used. The generated electric power P1 required by the electric equipment is constant, and therefore the engine 10 is also steadily operated at a constant engine speed N1. From this state, a case where the generated power P required by the electric device is increased by the operation of the electric device connected to the engine generator 1 will be described based on the control flow shown in FIG.

  The output power detection means 31b detects the generated power P every moment. In step S100, it is determined whether the load applied to the engine 10 has changed according to the detection result of the generated power P. Specifically, the engine 10 maintains the engine rotational speed N constant by the speed governor 11 unless instructed by the engine-side control device 50. Therefore, when the detected generated power P changes. It is assumed that the load applied to the engine 10 has changed due to the operation of the electrical equipment. When it is determined that the load has changed, the process proceeds to step S110.

  In step S110, the generated power P2 after it is determined that the load fluctuated in step S100 is detected and grasped. Thus, the process proceeds to step S120 in a state where the generated power P1 before the load change and the generated power P2 after the load change are grasped.

  In step S120, the output rate Pr (%) is calculated based on the generated power P1 before the load change and the generated power P2 after the load change.

  In step S130, if the output rate Pr (%) calculated in step S120 exceeds the threshold value B, the process proceeds to step S140, and if not, the process returns to step S100.

  The threshold value B is set to a certain ratio with respect to the generated power P1 before the load change. For example, when the threshold value B is determined to be 2% of the generated power P1 in view of the characteristics of electric equipment used and the work content, the process proceeds to step S140 when the output rate Pr (%) due to load fluctuation is greater than 2%. Will be. If the output rate Pr (%) due to load fluctuation is smaller than 2%, the process returns to step S100.

  In step S140, the target engine speed N2 is set. This is to increase the generated power P by increasing the engine speed N and to secure the required amount of power.

  Specifically, based on the correlation map between the generated power P and the engine speed N as shown in FIG. 3, the engine speed N2 corresponding to the generated power P2 required by the electrical equipment is called, and this is the target engine speed. The number N2. The correlation map is created by specifying the most appropriate engine speed N in consideration of the fuel consumption rate of the engine 10, the noise value, etc., on the premise that stable electric power can be supplied to the electrical equipment. is there.

  In step S150, an instruction is issued from the engine-side control device 50 to the step motor 11a so that the actual engine speed N2 matches the target engine speed N2 determined in step S140. Upon receiving the instruction, the step motor 11 a controls the speed governor 11 to increase the amount of fuel supplied from the fuel injection pump 12 to the engine 10. As a result, the engine speed N rises and is set to the target engine speed N2.

  As a result, as shown in FIG. 4, when the load fluctuation applied to the engine 10 is relatively small and the calculated output rate Pr1 does not exceed the threshold value B, the engine speed N remains constant. Therefore, the engine speed N is not frequently changed even in an operation in which a small load fluctuation is repeatedly performed, and a good driving feeling is ensured. In addition, when the load fluctuation applied to the engine 10 is relatively large and the calculated output rate Pr2 exceeds the threshold B, the generated power P also increases due to the increase in the engine speed N, so that stable power supply is realized. it can.

  Next, the control flow of the engine generator 1 according to the first configuration example will be described with reference to FIG. FIG. 6 shows the relationship between the generated power P and the engine speed N, and FIG. 7 shows the relationship between the engine speed N and the output rate Pr (%). The generated power Ps and the engine speed Ns are values when the engine 10 is rated.

  In step S200, the output power detection means 31b detects the generated power P every moment, and proceeds to step S210 in a state where the generated power P1 at a certain time and the generated power P2 after a certain time have been grasped.

  In step S210, the target engine speed N2 is set. This is to increase the generated power P by increasing the engine speed N and to secure the required amount of power.

  Specifically, based on the correlation map between the engine speed N and the generated power P as shown in FIG. 6, the engine speed N2 corresponding to the generated power P2 required by the electrical equipment is called, and this is the target engine speed. The number N2.

  The correlation map makes the change in the engine speed N small in a region where the required generated power P is relatively small, and increases the change in the engine speed N as the required generated power P increases, thereby generating the amount of power generation. Is set to ensure. Therefore, the correlation map in the first embodiment differs from the correlation map in that there is no region where the engine speed N is constant, and the power generation output is set smoothly over the entire region.

  In step S220, an instruction is issued from the engine-side control device 50 to the step motor 11a so that the actual engine speed N matches the target engine speed N2 determined in step S210. Upon receiving the instruction, the step motor 11 a controls the speed governor 11 to increase the amount of fuel supplied from the fuel injection pump 12 to the engine 10. As a result, the engine speed N rises and is set to the target engine speed N2.

  As a result, when the load applied to the engine 10 is small and the calculated output rate Pr1 is relatively small as shown in FIG. 7, the engine speed N is little changed and a small load fluctuation is repeatedly performed. However, the engine speed N is maintained substantially constant, and a good driving feeling is ensured. Further, as the generated power P required by the electrical equipment increases, that is, as the output rate Pr (%) increases (for example, the output rate Pr2), the engine speed N increases in a quadratic curve. Stable power supply can be realized due to the increase, and a smooth driving feeling can be ensured throughout.

  Next, referring to FIG. 8, the user can grasp that the load fluctuation applied to the engine 10 is equal to or greater than a predetermined value. For example, the second embodiment can avoid the stop of the engine 10 and the stop of the electrical equipment due to the load fluctuation. A control flow of the engine generator 1 will be described. FIG. 9 shows the relationship between the engine speed N and the output rate Pr (%). The generated power Ps and the engine speed Ns are values when the engine 10 is rated.

  In this embodiment, the inverter 30 is not provided, and the engine speed Ns during rated operation of the engine 10 as in a conventional engine generator is maintained constant regardless of the magnitude of the load. Only when Pr (%) exceeds a predetermined threshold C, the target engine speed N2 is changed.

  The threshold C and the target engine speed N2 can be arbitrarily set in consideration of the characteristics of the electric equipment used, the work contents, and the like. For example, the threshold C is a value about 5% smaller than the output rate Prmax calculated from the maximum load fluctuation allowed for the engine 10, and the target engine speed N2 is set to the maximum engine speed Nmax allowed for the engine 10. About 5% lower.

  In step S300, it is determined whether or not the load applied to the engine 10 has changed according to the detection result of the generated power P by the generator output determination unit 32c. If it is determined that the load has changed, that is, the load has been applied, the process proceeds to step S310.

  In step S310, the generated power P2 after it is determined that the load fluctuated in step S300 is detected. Thus, the process proceeds to step S320 in a state where the generated power P1 before the load change and the generated power P2 after the load change are grasped.

  In step S320, the output rate Pr (%) is calculated based on the generated power P1 before the load change and the generated power P2 after the load change.

  In step S330, when the output rate Pr (%) calculated in step S320 exceeds the threshold value C, the process proceeds to step S340. Otherwise, the process returns to step S300.

  In step S340, an instruction is issued from the engine-side control device 50 to the step motor 11a so that the actual engine speed N matches the predetermined target engine speed N2. Upon receiving the instruction, the step motor 11 a controls the speed governor 11 to increase the amount of fuel supplied from the fuel injection pump 12 to the engine 10. As a result, the engine speed N rises and is set to the target engine speed N2.

  As a result, the engine speed N increases only when the output rate Pr (%) calculated by the input load exceeds an arbitrarily set threshold value C, so that the load fluctuation applied to the engine 10 by the user is predetermined. It is possible to grasp that the value is equal to or greater than the value, and for example, it is possible to avoid the stop of the engine 10 or the stop of the electrical equipment due to the insufficient power generation output, and to ensure safety.

  Next, FIG. 10 shows a control flow of the engine generator 1 according to the third embodiment that shortens the settling time Ts and enables stable power supply. FIG. 11 shows changes over time in the load, the engine speed N, and the engine output EP. However, it demonstrates centering on step S440 used as a control flow different from 1st embodiment.

  As shown in FIG. 11, the engine 10 is applied with a constant load F1 and is steadily operated at the engine speed N1, and the output of the engine 10 at this time is defined as an engine output EP1.

  When the load applied to the engine 10 increases from the load F1 to the load F2 at the time t1, the engine speed N decreases instantaneously and then increases again, and becomes stable at the predetermined engine speed N2 at the time t2. This is an undershoot caused by a delay in response of the speed control mechanism 11 and the fuel injection pump 12 with respect to a sudden decrease in the engine speed N caused by load fluctuation. The period from the time t1 to the time t2 is the settling time Ts, and when the settling time Ts is long, there is a case where power supply to the electric equipment used is insufficient. Further, when the decrease in the engine speed N due to load fluctuation is large, the engine 10 may stop as it is.

  In step S440, the target engine output EP2 is provided for assisting the settling of the engine 10. This is to increase the engine output EP to quickly recover and increase the engine speed N2 to ensure a stable generated power P.

  The target engine output EP2 is created by specifying the most appropriate engine output increase amount for setting the engine speed N, and the engine output EP that is called from now on is set as the target engine output EP2.

  The target engine output EP2 is created by specifying the most appropriate engine output increase amount for shortening the settling time Ts with respect to the value of the output rate Pr (%), which is the exhaust gas of the engine 10. It is determined in consideration of characteristics. The target engine output EP2 is set so as to be larger than the engine output EP3 when the engine 10 is applied with a constant load F2 and is normally operated at the engine speed N2.

  In step S450, an instruction is issued from the engine-side control device 50 to the step motor 11a so that the actual engine output EP matches the target engine output EP2 determined in step S440. Upon receiving the instruction, the step motor 11 a controls the speed governor 11 to increase the amount of fuel from the fuel injection pump 12 to the engine 10. As a result, the engine output EP increases to the target engine output EP2.

  In addition, the engine-side control device 50 starts a countdown until the end of the increase in engine output simultaneously with the instruction to increase the fuel. This is to finish the increase of the engine output EP for assisting the settling at an appropriate timing, and the time Tc is the most appropriate from the calculated output rate Pr (%) or the decrease amount of the engine speed N. It is determined by specifying the engine output increase time.

  In step S460, when the countdown started in step S450 is completed, the process proceeds to step S470, and the increase in the engine output EP for assisting settling is stopped. When the predetermined time Tc has not elapsed, the engine output EP continues to increase.

  As a result, it is possible to improve the settling delay of the engine 10 due to the decrease in the engine speed N caused by the load fluctuation, and to stabilize the power supply.

  Next, FIG. 12 shows a control flow of the engine generator 1 according to the second configuration example for shortening the settling time Ts, and the description will start with step S540 as a control flow different from the first embodiment. FIG. 13 shows the relationship between the generated power P and the engine speed N.

  In step S540, the generator output determination unit 32c calculates the virtual generated power Pi from the generated voltage (referred to as “regulated generated voltage”) when the engine is rated and the measured current detected by the output power detecting means 31b. .

  In step S550, the virtual engine speed Ni corresponding to the virtual generated power Pi is called based on the correlation map between the generated power P and the engine speed N as shown in FIG. Since the virtual generated power Pi is calculated using the specified power generation voltage, the virtual generated power Pi has a higher value than the actual generated power P1, so that the called virtual engine speed Ni is also larger than the actual engine speed N1. .

  In step S560, an instruction is issued to step motor 11a to increase the fuel supply amount corresponding to virtual engine speed Ni determined in step S550. Upon receiving the instruction, the step motor 11a controls the speed governor 11 to increase the amount of fuel from the fuel injection pump 12 to the engine 10, thereby increasing the engine output EP and recovering from the decrease in the engine speed N. The rise is accelerated and the settling time Ts is shortened.

  In addition, the engine-side control device 50 starts a countdown until the end of the increase in engine output simultaneously with the instruction to increase the fuel. This is to finish the increase of the engine output EP for assisting the settling at an appropriate timing, and the time Tc is the most appropriate from the calculated output rate Pr (%) or the decrease amount of the engine speed N. It is determined by specifying the engine output increase time.

  In step S570, when the countdown started in step S560 is completed, the process proceeds to step S580, and the increase in the engine output EP for assisting settling is stopped. When the predetermined time Tc has not elapsed, the engine output EP continues to increase.

  As a result, it is not necessary to individually set a correlation map between the output rate Pr (%) and the engine output EP for various engine generators 1, and can be realized by the same simple control program. Man-hours can be reduced.

The block diagram which shows the structure of the engine generator which concerns on 1st embodiment of this invention. The control flowchart of the engine generator which concerns on 1st embodiment of this invention. The figure which shows the relationship between generated electric power and an engine speed. The figure which shows the relationship between an engine speed and an output rate. The control flowchart of the engine generator which concerns on a 1st structural example. The figure which shows the relationship between generated electric power and an engine speed. The figure which shows the relationship between an engine speed and an output rate. The control flowchart of the engine generator which concerns on 2nd embodiment of this invention. The figure which shows the relationship between an engine speed and an output rate. The control flowchart of the engine generator which concerns on 3rd embodiment of this invention. The figure which shows the change of a load, an engine speed, and an engine output. The control flowchart of the engine generator which concerns on a 2nd structural example. The figure which shows the relationship between generated electric power and an engine speed.

1 Engine generator 10 Engine 20 Generator 30 Inverter device 50 Engine side control device N Engine speed P Generated power Pr (%) Output rate

Claims (3)

An engine, a generator that is driven by the engine to generate electric power, an inverter device that converts electric power generated by the generator into AC power having a predetermined frequency, and a control that controls the operating state of the engine based on an engine map An engine generator having a device,
Calculate the output rate, which is the ratio of the generated power difference before and after the load change to the generated power before the load change,
The output rate is compared with a threshold value, and when the output rate is larger than the threshold value, the target engine speed corresponding to the generated power required by the electrical equipment connected to the engine generator is set,
The engine generator is called from the engine map created in consideration of a fuel consumption rate and a noise value of the engine so that a stable power supply to an electric device can be performed. . An engine, a generator that is driven by the engine to generate electric power, an inverter device that converts electric power generated by the generator into AC power having a predetermined frequency, and a control that controls the operating state of the engine based on an engine map An engine generator having a device,
With the actual engine speed set at the engine speed during rated operation, calculate the output rate that is the ratio of the generated power difference before and after the load change to the generated power before the load change and calculate the output rate. Compared to the threshold,
An engine generator that sets an actual engine speed to a target engine speed that is higher than an engine speed during rated operation when the output rate is greater than a threshold value . An engine, a generator that is driven by the engine to generate electric power, an inverter device that converts electric power generated by the generator into AC power having a predetermined frequency, and a control that controls the operating state of the engine based on an engine map An engine generator having a device,
Calculate the output rate, which is the ratio of the amount of power generation decrease when the engine speed decreases due to load variation to the power generation before load variation,
When the output rate is compared with a threshold and the output rate is greater than the threshold,
In order to increase the engine output determined by the engine load and the engine speed to increase the engine output to a predetermined engine speed and ensure stable power generation recovery,
In order to shorten the settling time to a predetermined engine speed, the target engine output is called from the engine map created by specifying the engine output increase amount in consideration of the exhaust gas characteristics, until the target engine output, An engine generator characterized by increasing the engine output.

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