JP5886071B2 - Engine-driven inverter generator control method and engine-driven inverter generator - Google Patents

Description

  The present invention relates to an engine-driven inverter generator control method and an engine-driven inverter generator, and more particularly, a method for controlling the rotational speed of an engine mounted on an engine-driven inverter generator, and the control method. The present invention relates to an engine-driven inverter generator.

  Engine-driven generators that generate power by driving the generator body with an engine are widely used as emergency power supplies in the event of a power failure, and in particular, components such as the engine and generator body are housed in a package. Package-type engine-driven generators are widely used because of their portability, such as in construction sites and event venues where it is necessary to secure power supplies outdoors.

  In such an engine-driven generator, when the AC generated in the generator body is output as it is, the frequency of the AC output from the generator body is determined by the rotational speed of the generator body. Therefore, it is necessary to perform “constant speed control” for maintaining the generator main body, and hence the engine speed at a constant speed.

  However, the generator itself in an operation state with a constant rotation speed shows a “drooping characteristic” in which the output voltage decreases as the load current increases and the output voltage increases as the load current decreases. When an engine-driven generator that is controlled in this way is connected to a load that consumes less power than the rated output power of the generator, the output voltage increases as the load current decreases. Thus, the amount of electric power supplied to the magnitude of the connected load becomes excessive by this voltage increase, and the engine consumes useless fuel.

  Therefore, without supplying the AC output from the generator itself to the load as it is, it is first converted to DC through a converter composed of diodes, etc., and then converted to AC at the desired frequency with an inverter. By performing “constant voltage control” that controls the engine speed so that the output voltage becomes a constant voltage regardless of load fluctuations, the frequency of power supplied to the load In addition to being determined by the rotational speed, the rotational speed of the engine is changed according to the magnitude of the connected load.

  The opening of the throttle valve that supplies fuel to the engine with respect to a change in load current when performing such constant voltage control is represented by a curve Ld that indicates the correspondence described in (i) to (v) below. Based on this control, it has been proposed that the engine fuel consumption is minimized in an engine-driven inverter generator (Patent Document 1, column 3, line 37 to column 4, line 43). Line reference).

(i) As shown in FIG. 9, on the performance diagram showing the correlation between the rotational speed and the output of the engine, the throttle valve is positioned at a position where the engine is at a predetermined rotational speed (for example, 4000 min ⁻¹ ) without load. By changing the load applied to the engine in this state, the curve indicating the correspondence between the load change (change in output (kW)) and the change in rotation speed (min ^-1 ) (valve) A load-rotational speed curve a1) at a constant opening is obtained.

Similarly, the throttle valve opening is fixed at a position where the rotational speed at no load becomes another rotational speed (3800, 3600, ... 2400min ^-1 as an example), and the load applied to the engine is changed. , Curve showing the correspondence between load change (output (kW) change) and rotation speed (min ^-1 ) change (load-rotation speed curves a2, a3,..., A9 when the valve opening is constant) Ask for.

 (ii) On the load-rotational speed curve (a1 to a9) when each valve opening is constant, the points where the fuel consumption rate (g / kW · hr) is the same are connected with a line to obtain the same fuel efficiency. A rate curve Le is obtained (see FIG. 9).

 (iii) Find contact points (B1, B2,... B10) between the calculated equal fuel consumption rate curve Le and a line parallel to the horizontal axis of the graph, and connect these contact points (B1, B2,... B10). By obtaining the curve, a minimum fuel consumption curve Lf indicating the correspondence between the output and the rotational speed for operating the engine with the least fuel consumption is obtained (see FIG. 9).

 (iv) A load-rotational speed curve (P1, P2,..., P10) at a constant valve opening through each of the contacts (B1, B2,... B10) is obtained, and these curves (P1, P2,. ... (P10) is determined for each rotation speed (N1, N2,... N10) at no load (see FIG. 9).

 (v) Plots of intersections of the rotational speeds (N1, N2,... N10) and the outputs (PS1, PS2,... PS10) at the contacts (B1, B2,... B10) (D1 , D2,... D10), and plots (D1, D2,... D10) are obtained to obtain a control curve Ld of the throttle valve (see FIG. 10).

 (vi) Detected based on the engine control curve Ld in FIG. 10 according to the correspondence between the engine output (PS1, PS2,... PS10) and the load current LI (C1, C2,... C10). The rotation speed N corresponding to the load current IL (for example, N is N1 when IL is C1) is determined, and the opening of the throttle valve is set so that the calculated rotation speed (N1) is generated at no load. Control.

  As a result, the engine speed changes according to the minimum fuel consumption curve Lf with respect to the load fluctuation, and the engine can be operated with the minimum fuel consumption.

  Although not described in Patent Document 1, a line connecting the maximum output points that can be output by the engine at each rotational speed is the maximum output curve Lmax of the engine (see FIG. 9).

Japanese Examined Patent Publication No. 63-46253

  In the method described in Patent Document 1 described above, the load current IL and the rotational speed N (throttle valve opening) set to minimize the fuel consumption of the engine provided in the inverter-type portable generator. The degree of rotation of the engine can be changed on the minimum fuel consumption curve Lf by previously obtaining the relationship with the engine speed) by the method described above and controlling the opening of the throttle valve based on this relationship. As a result, the inverter-type portable generator can be efficiently operated with the minimum amount of fuel.

  However, when the rotational speed of the engine provided in the inverter generator is controlled by the method described in Patent Document 1, there are the following problems.

  As described with reference to FIG. 9, the equal fuel consumption rate curve Le appears as a shape in which concentric circles are distorted. However, as shown in the characteristic diagram of the engine shown in FIG. The fuel consumption rate curve Le may not appear as a form with less dynamic distortion, but may appear as a more distorted and biased shape as shown in FIG.

  As an example, when the minimum fuel consumption curve Lf is obtained based on the characteristic diagram of the engine shown in FIG. 2, the minimum fuel consumption curve Lf changes gently in the range of points B1 to B3 and points B5 to B7 in FIG. However, when the engine speed is continuously increased or decreased according to such a minimum fuel consumption curve Lf, the engine has a large difference in inclination such that the inclination increases in the range of points B3 to B5. Because the engine speed changes slowly, the engine cannot follow this speed change quickly, or the engine sound changes in response to the speed change, which is louder than the actual volume. There was a problem of being heard uncomfortablely.

  Further, depending on the shape of the equal fuel consumption rate curve Le, the minimum fuel consumption curve Lf partially overlaps the maximum output curve Lmax of the engine (the range of points B5 to B7 in FIG. 2) or does not overlap the maximum output curve Lmax. Even if it appears, it may appear so as to approach the maximum output curve Lmax.

  However, the engine can be operated only on the low output side (lower side of the maximum output curve Lmax in FIG. 2) with respect to the maximum output curve Lmax, and the engine rotation is based on such a minimum fuel consumption curve Lf. When controlling the speed, the engine is operated at the maximum output, or at an output with little margin for the maximum output, so changes in the operating environment (for example, changes in atmospheric pressure, temperature, etc.), filter Even if the engine output decreases slightly due to deterioration over time such as clogging or changes in the quality of the fuel used, the rotational speed control according to the minimum fuel consumption curve Lf cannot be performed, and the connected load The engine output is insufficient with respect to the size, and therefore the output power is also insufficient.

  Furthermore, when the load suddenly increases, if the engine output at that rotational speed is small, the increase in engine rotational speed is delayed with respect to the increase in load, resulting in insufficient power supply to the load. Otherwise, there is a possibility that the load that is being started is stopped, or that the load is unsuccessful and that the engine itself may stall in some cases.

  Accordingly, the present invention has been made to solve the above-described drawbacks in the prior art, and in an engine-driven inverter generator capable of changing the rotational speed of the engine in accordance with load fluctuations, the fuel consumption can be reduced. In addition, the engine speed can be quickly responded to load fluctuations, engine stalls occur due to response delays, and load is stopped or started during startup due to insufficient output power. An engine-driven inverter generator control method that can suitably prevent the occurrence of malfunctions such as failures, and can also prevent the generation of harsh engine noise that changes with speed, and the control method can be realized. An object of the present invention is to provide an engine driven inverter generator.

  Hereinafter, means for solving the problem will be described together with reference numerals used in the embodiment for carrying out the invention. This code is used to clarify the correspondence between the description of the scope of claims and the description of the mode for carrying out the invention. Needless to say, it is used in a limited manner for the interpretation of the technical scope of the present invention. It is not a thing.

In order to achieve the above object, the control method of the engine-driven inverter generator 1 according to the present invention includes an engine 21, a generator main body 22 driven by the engine 21, and an alternating current generated in the generator main body 22 converted into a direct current. A converter 31 for conversion and an inverter 32 for converting the direct current output from the converter 31 to a predetermined alternating current and supplying the converted alternating current to the load are provided, and the engine speed is controlled according to the detected change in power consumption on the load side. In the engine driven inverter generator 1 that
On the engine performance diagram showing the relationship between the output (vertical axis) and the rotational speed (horizontal axis) of the engine 21, outputs of a predetermined margin Δ1 and a power generation loss Δ2 from the maximum output curve Lmax of the engine 21 One generator output line Lg obtained by subtracting, and further, for any engine output between 0 and the maximum output based on the equal fuel consumption rate curve Le shown on the performance diagram and the engine output The minimum fuel consumption curve Lf is obtained from the point where the fuel consumption is minimized.
When the minimum fuel consumption curve Lf is located on the low output side with respect to the generator output line Lg in the entire rotation speed range of the engine, the minimum fuel consumption curve Lf is obtained by deforming it into an approximately smooth line. The approximate line is the engine speed control line Lc (see FIG. 7),
In a part of the engine speed range (for example, range X in FIG. 6), the minimum fuel consumption curve Lf is positioned on the low output side with respect to the generator output line Lg, and another speed range (for example, FIG. 6). When the minimum fuel consumption curve Lf overlaps the generator output line Lg and / or is located on the high output side with respect to the generator output line Lg in the middle range Y), the partial rotational speed range (for example, A connection curve formed by connecting the minimum fuel consumption curve Lf in the range X) in FIG. 6 and the generator output line Lg in the other rotational speed range (for example, the range Y in FIG. 6) is approximately smooth. The approximate line obtained by transforming the line into the line is the engine speed control line Lc (see FIG. 6).
When the minimum fuel consumption curve Lf overlaps with the generator output line Lg and / or is located on the high output side with respect to the generator output line Lg in the entire rotational speed range of the engine, the generator output line Lg is The engine speed control line Lc (see FIG. 8),
Based on the engine speed control line Lc, an engine speed that generates an output corresponding to the detected power consumption value on the load side is obtained, and the obtained speed is used as the target speed to approach the target speed. Thus, the rotational speed of the engine is controlled.

  In the above control method, the predetermined margin Δ1 subtracted from the maximum output curve Lmax can be set large on the low engine speed side and small on the high engine speed side (Claim 2: see FIGS. 4 and 5). ).

  In addition, the predetermined margin Δ1 subtracted from the maximum output curve Lmax is the maximum that can occur at the rotational speed in a state of operation at a predetermined rotational speed (for example, the minimum rotational speed without a load connected). It is preferable to set by experimentally obtaining in advance a value that can maintain the output of a predetermined minimum voltage value (for example, 140V) when a load value increase (connection of the maximum load that can be connected) is caused ( Claim 3).

The engine-driven inverter generator 1 of the present invention includes an engine 21, a generator main body 22 driven by the engine 21, a converter 31 that converts alternating current generated in the generator main body 22 into direct current, and the converter 31. An inverter 32 that converts the output direct current into a predetermined alternating current and supplies it to the load is provided, and the storage means according to the change in the power consumption on the load side detected by the power consumption detection means (the control unit 33 in the embodiment) The engine drive type inverter generator provided with an engine control device (in the embodiment, realized by the controller 8, the ECU 26, the electronic governor 24, and the rotation speed sensor 25 as a whole) according to the correspondence stored in advance In 1,
The storage means of the engine control device (in the embodiment, the storage means of the controller 8) corresponds to the change in the power consumption on the load side obtained based on the engine speed control line Lc and the power consumption value. The correspondence relationship with the rotational speed of the engine that generates the output is stored (claims 4 to 6).

  With the configuration of the present invention described above, according to the engine-driven inverter generator 1 of the present invention, the following remarkable effects can be obtained.

  The engine rotation speed control line Lc used as a reference for obtaining the correspondence relationship between the power consumption value on the load side and the engine rotation speed used in the rotation speed control of the engine 21 is a straight line approximated to the minimum fuel consumption curve Lf or Since it was obtained as a curve, the fuel consumption of the generator 1 could be reduced by controlling the engine speed according to this speed control line Lc.

  In addition, since the rotational speed control line Lc is obtained as a smooth approximation line that eliminates the change appearing on the minimum fuel consumption curve Lf, the rotational speed change with respect to the output of the engine 21 (load side power consumption) changes. Not only has the smoothness improved the followability of the engine speed change to the power consumption change on the load side, but also the engine speed can be increased or decreased continuously. By changing the engine speed at a constant rate, it was possible to eliminate the “noisiness” of engine noise caused by the uncomfortable feeling that accompanies the change in rotational speed.

  The rotational speed control line Lc is formed as a curve obtained by subtracting the output of the predetermined margin Δ1 and the power generation loss Δ2 from the maximum output curve Lmax of the engine 21. On the other hand, since the engine is operated at a rotational speed that takes into account a predetermined margin Δ1 and power generation loss Δ2, the environment deteriorates due to environmental changes (atmospheric pressure, temperature), filter clogging, etc., and the quality of fuel used varies. Even if there was a slight decrease in engine output due to changes in performance due to this, this decrease could be compensated.

  Further, as described above, since the engine 21 is always operated with a predetermined margin, even if a sudden load fluctuation occurs, the engine output and the rotational speed follow the load fluctuation. Such as stalling of the engine caused by a delay in the increase of the engine speed relative to the increase of load, stoppage of the load during start-up caused by insufficient supply power, failure of starting the load, etc. The occurrence of defects could also be suitably prevented.

  It should be noted that when the engine speed is low and when the engine speed is high, the engine rotational response is different. When the engine speed is low, the response speed is slow and when the engine speed is high, the response speed is high. By making the above-mentioned margin Δ1 subtracted from the curve Lmax larger on the low speed side of the engine and smaller on the high speed side, the response speed can be made uniform in any speed range from low speed to high speed. I was able to plan.

  In addition, when the margin Δ1 subtracted from the maximum output curve Lmax is operated at a predetermined rotational speed (for example, the minimum rotational speed without a load connected), the maximum load value increase that can occur at the rotational speed By setting a value that can maintain the output of a predetermined minimum voltage value (for example, 140V as an example) when experimentally generated (connection of the maximum load that can be connected as an example) The voltage can always be maintained above a certain value, and it is possible to more reliably prevent malfunctions such as stopping of the load during start-up due to delay in following changes in engine speed with respect to load fluctuations. did it.

The block diagram which shows the example of 1 structure of the engine drive type inverter generator of this invention. Engine performance diagram (representing the relationship between maximum output curve Lmax, minimum fuel consumption curve Lf, and equal fuel consumption rate curve Le). Engine performance diagram (example showing the relationship between the maximum output curve Lmax and the generator output line Lg, and providing a constant output margin in the entire rotational speed range). Performance chart of the engine [example showing the relationship between the maximum output curve Lmax and the generator output line Lg (straight line), with a large output margin on the low rotation side and a small output on the high rotation side. ]. Performance chart of the engine [Example showing the relationship between the maximum output curve Lmax and the generator output line Lg (curve), with a large output margin on the low rotation side and a small output on the high rotation side. ]. Engine performance diagram (Explanation of how to determine the engine speed control line Lc. Part of the minimum fuel consumption curve Lf is on the low output side of the generator output line Lg, and the other part is high output. Explanatory drawing when it is on the side.) Engine performance diagram (an explanatory diagram of how to determine the engine speed control line Lc, and an explanatory diagram when the entire range of the minimum fuel consumption curve Lf is on the lower output side than the generator output line Lg). Engine performance diagram (an explanatory diagram of how to determine the engine speed control line Lc, and an explanatory diagram when the entire range of the minimum fuel consumption curve Lf is on the higher output side than the generator output line Lg). Engine performance diagram (corresponding to FIG. 3 of Patent Document 1). Load current (engine output) -rotational speed (valve opening) correlation diagram (corresponding to FIG. 4 of Patent Document 1: correlation diagram used for throttle valve opening control).

  Hereinafter, an engine-driven inverter generator of the present invention and engine speed control performed in the engine-driven inverter generator will be described with reference to the accompanying drawings.

[Configuration of generator]
(1) Overall Configuration In FIG. 1, reference numeral 1 denotes an engine-driven generator according to the present invention. The engine-driven generator 1 has an engine 21 and a generator body 22 driven by the engine 21. The power conversion unit 3 includes a power generation unit 2, a converter 31 that converts alternating current generated in the power generation unit 2 into direct current, an inverter 32 that converts the direct current from the converter 31 into alternating current of a predetermined frequency, and outputs the alternating current. 3 is provided with a waveform shaping unit 4 including filters 41 to 43 for improving the output waveform, and the AC output shaped by the waveform shaping unit 4 is taken out from an output terminal block 6 connected via a breaker 5 or the like. Can be done.

  Further, the engine-driven inverter generator 1 controls the operations of the power generation unit 2 and the power conversion unit 3 based on detection signals (including calculated values) from the control unit 33 and the like provided in the power conversion unit 3. A controller 8 is provided, and corresponds to the setting made by the operator by operating the switches (71, 72, 76) provided in the input means 7, and the controller 8 controls the engine-driven inverter generator 1. It comes to perform control.

(2) Power Generation Unit The power generation unit 2 includes an engine 21, a generator main body 22 driven by the engine, and an engine control unit (ECU) 26 that controls the rotational speed of the engine. The rotating shaft of the generator main body 22 is connected, and the engine 21 and the generator main body 22 rotate in synchronization.

  In this embodiment, the generator body 22 is a permanent magnet generator, and is driven by the engine 21 described above to generate and output a three-phase alternating current having a frequency corresponding to the rotational speed.

  The engine 21 is provided with an electronic governor 24 that adjusts the amount of fuel injected into the combustion chamber in accordance with the received electrical signal, and a rotational speed sensor 25 that detects the rotational speed of the engine.

  The engine control unit (ECU) 26 is an electronic control device for comprehensively performing electrical control of the engine 21, and by transmitting a control signal to the electronic governor 24 provided in the engine 21, The injection amount, the injection timing, and the like can be controlled. The rotational speed (measured rotational speed) of the engine 21 detected by the rotational speed sensor 25 and the rotational speed (target rotational speed) output from the controller 8 to be described later. A fuel control signal for instructing the fuel injection amount (or fuel increase / decrease amount) is transmitted to the electronic governor 24 so that the deviation of the above becomes zero.

  Therefore, in the embodiment shown in FIG. 1, a controller 8, which will be described later, an ECU 26 controlled by the controller 8, an electronic governor 24 controlled by the ECU 26, and a rotation that feeds back the rotational speed of the engine 21 to the ECU 26. The speed sensor 25 constitutes an “engine control device” that controls the rotational speed of the engine.

  In this embodiment, the rotation speed sensor 25 transmits a rotation pulse signal at every predetermined rotation angle of the engine 21, and the ECU 26 calculates an actual rotation speed based on the rotation pulse signal.

(3) Power Conversion Unit The power conversion unit 3 includes a converter 31 that converts the three-phase alternating current output from the generator body 22 into direct current, and an inverter that converts the direct current output from the converter 31 into a predetermined three-phase alternating current. 32, current detection means 34 for detecting the current value of the three-phase alternating current input to the converter 31, and current detection means 35 for detecting the current value of the three-phase alternating current output from the inverter 32. The control unit 33 which controls the converter 31 and the inverter 32 so that the power of the frequency and voltage commanded by the controller 8 is output, and detects (calculates) the power consumption value on the load side and outputs it to the controller 8. Is provided.

  The three-phase alternating current output from the generator main body 22 is input to a converter 31 provided in the power conversion unit 3 and rectified to direct current by switching a plurality of transistors built in the converter 31, and then the capacitor Is smoothed and output.

  In the present embodiment, the converter 31 is provided with a booster circuit (not shown) that outputs a predetermined DC voltage value higher than the input three-phase AC voltage value, and the capacitor is used for smoothing and load variation. Therefore, the DC voltage value can be stabilized by the action of the booster circuit and the capacitor.

  The direct current converted from the three-phase alternating current by the converter 31 is then input to the inverter 32 also provided in the power conversion unit 3 so that the inverter has the predetermined frequency and output voltage value set by the input means 7. A plurality of transistors built in 32 are switched, and converted into a three-phase alternating current by a PWM (pulse width modulation) method.

  The converter 31 and the inverter 32 are controlled by a control unit 33 that is an electronic control unit. The control unit 33 includes a current value of each phase of the three-phase AC input to the converter 31 detected by the current detection unit 34. , The DC voltage value between the converter 31 and the inverter 32, the current value of each phase of the three-phase AC output from the inverter detected by the current detection means 35, and the predetermined rotation angle of the engine 21, respectively. In addition, a rotation pulse signal transmitted from the rotation speed sensor 25, a frequency and output voltage command signal transmitted from the controller 8, and the like are input.

  The control unit 33 estimates the electrical angle of the generator body 22 from the rotation pulse signal, and then converts the current value of each phase of the three-phase AC input to the converter 31 into a q-axis current value and a d-axis current value. An electrical angle is obtained based on the q-axis current value and the d-axis current value, the estimated electrical angle is replaced with the electrical angle, a PWM signal is generated based on the electrical angle, and the generated PWM signal is sent to the converter 31. Output to each of the built-in transistors. Furthermore, an electrical angle is generated based on the frequency command signal received from the controller 8, and based on the generated electrical angle, the output voltage command signal output from the controller 8, and the DC voltage value between the converter 31 and the inverter 32. A PWM signal is generated, and the generated PWM signal is transmitted to each of a plurality of transistors built in the inverter 32.

  In addition, the control unit 33 converts the current value of each phase of the three-phase AC output from the inverter 32 from an electrical angle generated based on the frequency command signal into a q-axis current value and a d-axis current value. The power consumption of the load is calculated based on the current value and the d-axis current value and the output voltage command signal (voltage indication value) received from the controller 8, and the calculated power consumption is output to the controller 8 as a power value. In this embodiment, the power consumption calculated based on these data is further subjected to a predetermined correction and then output to the controller.

  That is, in the engine-driven inverter generator 1 of the present embodiment in which the waveform shaping unit 4 (filter circuit) is provided after the output from the inverter 32, a voltage drop occurs in the waveform shaping unit 4, etc. The output voltage of 32 does not match the output voltage of the generator. Therefore, in this embodiment, the control unit 33 is made to calculate the power consumption on the load side using the voltage instruction value received from the controller 8.

  Therefore, a correction conversion formula is experimentally determined in advance by comparing the calculated power value in the control unit 33 with the actual measured value of the consumed power, and the calculated power consumption is corrected by this correction conversion formula. After that, the data is output to the controller 8.

  As described above, in the present embodiment, the control unit 33 realizes a detection means for detecting the power consumption value on the load side. However, the means for detecting the power consumption on the load side is the power consumption on the load side. Any device can be used as long as it can detect electric power. For example, the current detection means 35 is used as the detection means, or a separate current detection means is provided between the waveform shaping unit 4 and the load and the terminal block 6. This may be used as detection means, and detection signals from these detection means may be directly input to the controller 8 described later as information indicating the power consumption value on the load side. The correspondence relationship for determining the target rotational speed from the current value detected by the detecting means is stored.

  As described in the description of the ECU 26, in the present embodiment, the ECU 26 is designed to calculate the rotational speed of the engine from the rotational pulse signal transmitted from the rotational speed sensor 25 of the engine 21. Instead of the configuration, the control unit 33 is provided with a function of calculating the engine rotation speed (measured rotation speed) based on the rotation pulse signal, and outputs the rotation speed thus calculated to the controller 8 described later. You may comprise.

(4) Waveform shaping unit The three-phase alternating current having a predetermined frequency output from the power conversion unit 3 is then subjected to waveform shaping via the waveform shaping unit 4 and output to a load connected to the output terminal block 6. Is done.

  In the present embodiment, the waveform shaping unit 4 is constituted by an LC filter constituted by an AC reactor 41 and a filter capacitor 42 and a common mode choke 43, and the inverter 32 is constituted by the LC filter (41, 42). In addition to improving the output current / voltage waveform, the harmonics and high frequencies are removed to make the three-phase alternating current close to a sine wave, and the common mode choke 43 removes common mode noise.

(5) Controller The power consumption value on the load side output from the control unit 33, the rotational speed of the engine 21 received from the ECU 26, and the line voltage value between the three-phase AC phases output from the waveform shaping unit 4 Are input to the controller 8 constituted by a microcontroller or the like.

  In addition, set values such as an output frequency and an output voltage are input to the controller 8 by operating switches (71, 72, 76) provided in the input means 7 described later.

  In accordance with the program stored in the storage means, the controller 8 outputs the power consumption and the rotational speed transmitted from the control unit 33, the line between the three-phase AC phases output from the waveform shaping unit 4 and detected by the power conversion unit 3. Based on the inter-voltage value, the ECU 26 and the control unit 33 are instructed to control the engine 21 and the converter 31 and the inverter 32 so that the power of the frequency and voltage specified by the input means 7 can be output. Send a signal.

  Among such controls, as a reference when performing the engine speed control, the storage means of the controller 8 stores in advance the correspondence between the power consumption value on the load side and the engine speed of the engine 21, The controller 8 obtains the engine rotation speed corresponding to the power consumption value on the load side received from the control unit 33 based on the correspondence relationship, and uses the obtained rotation speed as the target rotation speed to measure the engine rotation speed (actual measurement). A command signal is output to the ECU 26 so as to perform control to bring the value) close to the target rotational speed.

  In the present embodiment, such a correspondence relationship is stored as the rotation speed correspondence table 81. However, such a correspondence relationship does not necessarily have to be stored as the rotation speed correspondence table 81. It may be stored in any state as long as the engine speed (target speed) can be obtained from the detected power consumption value on the load side.

  Thus, by storing the correspondence relationship between the power consumption value on the load side and the rotation speed of the engine 21 in the storage means as the rotation speed correspondence table 81, the controller 8 receives from the control unit 33 which is the power consumption detection means. Based on the power consumption value thus obtained, the target rotational speed of the engine 21 is obtained by referring to the above-described rotational speed correspondence table 81, and the above-described command signal is output to the ECU 26.

  The correspondence relationship between the power consumption on the load side stored in the storage means of the controller 8 and the rotational speed of the engine 21, in the present embodiment, the rotational speed correspondence table 81 is the engine rotational speed control obtained by the following method. It can be determined based on the line Lc.

  The rotational speed control line Lc can be obtained on the engine performance diagram showing the relationship between the output of the engine 21 and the rotational speed. In obtaining the rotational speed control line Lc, first, the maximum output of the engine mounted on the generator is obtained. A curve Lmax, an equal fuel consumption rate curve Le, and a minimum fuel consumption curve Lf are obtained.

  FIG. 2 is an engine performance curve diagram showing the maximum output curve Lmax, the equal fuel consumption rate curve Le, and the minimum fuel consumption curve Lf of the engine mounted on the generator of the present embodiment. The equal fuel consumption rate curve Le is 255 g / Fuel consumption for any engine output between 0 and maximum output based on each equal fuel consumption rate curve Le and engine output, calculated in steps of 5g / kW · h from kW · h to 225g / kW · h The minimum fuel consumption curve Lf is obtained by connecting the points B1 to B7 that minimize the curve with a curve.

  It should be noted that the equal fuel consumption rate curve Le and the maximum output curve Lmax can be obtained by the same method as that of the prior art described with reference to FIG.

  When the maximum output curve Lmax of the engine is obtained as described above, the generator output line Lg is obtained next.

  As shown in FIGS. 3 to 5, the generator output line Lg shows outputs of a predetermined margin Δ1 and a power generation loss Δ2 on the engine maximum power curve Lmax obtained earlier on the engine performance diagram. It can be obtained as a straight line or a curve obtained by subtraction.

  Here, the margin Δ1 to be subtracted from the maximum output curve Lmax is a constant width parallel to the maximum output curve Lmax as shown in FIG. 3 by subtracting a constant value in the above range of the rotation speed regardless of the engine speed. 3 may be provided (see the broken line in FIG. 3), or, as shown in FIGS. 4 and 5, a large margin Δ1a on the low speed side of the engine and a small margin Δ1e on the high speed side. It may be taken.

  This margin Δ1 can be obtained experimentally based on load fluctuations that can occur in the generator. As an example, in the present embodiment, when a load fluctuation of the maximum possible width occurs. Even so, this margin is set so that the output voltage of the generator can always be maintained above a certain value (140 V or more in this embodiment).

In the embodiment shown in FIG. 3, the rotational speed on the low speed side of the engine, for example, connected to the generator 1 for the engine in the operating state at the minimum rotational speed (1300 min ⁻¹ ) with no load connected. By providing a margin Δ1 that can maintain the minimum output voltage (140V) when the maximum possible load is connected over the entire range of engine speed, the margin Δ1 is subtracted from the maximum output curve Lmax. The broken line in FIG. 3 showing the above state is set so as to appear as a line parallel to the maximum output curve Lmax.

  Further, in the embodiment shown in FIG. 5, the maximum load that can be generated at each of a plurality of rotational speeds (r1 to r5 in the illustrated example) in the rotational speed range of the engine from the lowest speed to the highest speed. The margins that can cause the increase and maintain the above-mentioned minimum output voltage (140V) are measured and plotted as appropriate margins Δ1a to Δ1e at the respective rotation speeds r1 to r5. May be obtained as a line indicating a state in which a margin is subtracted from the maximum output curve Lmax.

  In the embodiment described with reference to FIG. 3 and FIG. 5, the line (broken line in the figure) representing the state excluding this margin Δ1 is shown as a “curve”. If a margin can be secured, a line indicating a state after the margin is removed may be obtained as a “straight line” as indicated by a broken line in FIG.

  Further, the output corresponding to the power generation loss Δ2 is further subtracted from the aforementioned maximum output curve Lmax of the engine, thereby obtaining a “generator output line” indicated by a symbol Lg in FIGS.

  As the power generation loss Δ2, the loss based on the power generation efficiency of the generator main body 22, the conversion loss generated in the converter 31 and the inverter 32, the loss in the waveform shaping unit 4, the control unit 33, the controller 8, the control device such as the ECU 26, etc. The power consumption is determined including all power losses that occur in the engine-driven inverter generator 1.

  In the embodiment shown in FIG. 3, the power generation loss Δ2 is shown as being subtracted from a constant value regardless of the engine speed, as in the case of the margin Δ1, but the engine of this embodiment In the drive type inverter generator 1, out of this power generation loss Δ 2, the loss generated in the converter 31 and the waveform shaping unit 4, and the power consumption in the control device are substantially constant regardless of the engine speed change. As shown, the loss in the inverter 32 and the loss in the generator body 22 tend to increase as the engine speed increases, and the power generation loss Δ2 as a whole also increases as the speed increases. As shown in FIG. 4 and FIG. 5, the power generation loss Δ2 is experimentally obtained in advance, and the engine rotational speed is shifted to the high speed side. Along with this, the power generation loss Δ2 was increased.

  Thus, the generator output line Lg obtained by subtracting the necessary margin Δ1 and the power generation loss Δ2 from the maximum output curve of the engine indicates the maximum output of the engine in practical use. The area below the plane of the machine output line Lg is the actual engine use area.

  When the generator output line Lg and the minimum fuel consumption curve Lf are obtained on the engine performance diagram as described above, the following method is used based on the relative positional relationship between the generator output line Lg and the minimum fuel consumption curve Lf. Thus, the engine speed control line Lc is obtained.

  As shown in FIG. 6, on the output diagram of the engine, the minimum fuel consumption curve Lf is located on the low output side (lower side of the page) with respect to the generator output line Lg in a part of the rotational speed range (range X). When the minimum fuel consumption curve Lf overlaps with the generator output line Lg and / or is located on the high output side (upper side of the page) with respect to the generator output line Lg in another rotational speed range (range Y), the range X Assume a connection curve in which the minimum fuel consumption curve Lf of the portion and the generator output line Lg in the range Y are connected.

  Then, an approximate line representing the connection curve obtained in this way, which is obtained by shaping the connection line into a smooth line with less unevenness, is obtained by, for example, the least square method, and this is obtained by controlling the rotational speed of the engine. Let it be line Lc.

  In the example shown in the drawing, the engine speed control line Lc is obtained as a curve. However, it may be obtained as a straight line as long as it is an approximate line of the above-described connection curve.

  Further, the engine rotational speed control line Lc is shaped to be equal to or less than the output of the generator output line Lg, regardless of whether it is obtained as a straight line or a curve.

  In contrast to the engine speed control line Lc described above with reference to FIG. 6, the minimum fuel consumption curve Lf is lower than the generator output line Lg over the entire range of the engine speed as shown in FIG. When it appears on the output side, an approximate line with the minimum fuel consumption curve Lf as a smooth line is obtained, and this is set as the engine speed control line Lc.

  In the example shown in FIG. 7, the engine rotational speed control line Lc may be determined to be a straight line, and the engine rotational speed control line Lc is on the low output side with respect to the generator output line Lg. Ask to appear.

  Further, the minimum fuel consumption curve Lf overlaps with the generator output line Lg and / or is located on the high output side with respect to the generator output line Lg (in the example of FIG. When the entire curve is located on the high output side with respect to the generator output line Lg), the generator output line Lg is directly used as the engine speed control line Lc (Lg = Lc).

  Here, there is a direct correspondence between the output of the engine 21 and the power consumption on the load side. The output axis of the engine performance diagram shows the power consumption value on the load side according to this correspondence. They can be overlapped (see FIG. 10).

  Therefore, according to the correspondence indicated by the engine speed control line Lc, it is possible to obtain the correspondence between the power consumption value on the load side and the engine speed that generates the output corresponding to this. The obtained correspondence relationship is stored in the storage means provided in the controller 8 as the aforementioned rotational speed correspondence table 81 or as a mathematical expression representing this rotational speed control line Lc.

(7) Input means Reference numeral 7 in FIG. 1 is provided with switches for setting the output frequency and output voltage of the engine-driven inverter generator 1 and performing operations such as starting and stopping. It is also an input means such as an operation panel.

  In the present embodiment, the input means 7 is provided with a frequency changeover switch 71, a voltage changeover switch 72, and a starter switch 76.

  Of these, the frequency selector switch 71 is capable of switching the output frequency output from the engine-driven inverter generator 1 between 50 Hz and 60 Hz, which is adopted as a commercial power source in Japan in this embodiment. The voltage changeover switch 72 enables the output voltage of the engine-driven inverter generator 1 to be switched between 200 V and 220 V, and the operator operates the frequency changeover switch 71 and the voltage changeover switch 72. When the frequency and voltage are switched, the controller 8 outputs a command signal to the control unit 33 so that the set frequency and voltage are output along with the switching of the switch, and the converter 31 and the inverter 32 according to the command signal are output. Is controlled by the control unit 33.

  Further, reference numeral 76 in FIG. 1 denotes a starter switch. The starter switch 76 has a “stop” position in which power is not supplied to the engine 21, the controller 8, the control unit 33, and other electrical components, and the engine 21 and electrical components. A switch between an “operating” position where energization of the engine is started and the engine 21 can be operated, and a “starting” position where energizing a cell motor (not shown) provided in the engine 21 and starting the engine 21 is performed. In this embodiment, a switch that can be switched between the positions by inserting a key is used as the starter switch.

  In the illustrated embodiment, the starter switch 76 is configured so that the three positions of stop, operation, and start can be switched with a single switch. For example, “stop” and “operation” A switch for switching between positions (for example, a switch) and a switch for starting a cell motor (for example, a momentary switch) may be provided separately.

[Description of operation]
The operation of the engine-driven inverter generator 1 of the present invention configured as described above will be described as follows.

  When the output frequency and the output voltage are set by operating the frequency selector switch 71 and the voltage selector switch 72 provided in the input means 7, and the starter switch 76 is moved from the "running" position to the "start" position, the engine 21 is provided. The cell motor (not shown) is energized, and the engine 21 is started by the rotation of the cell motor. After the engine 21 is started, the starter switch 76 is returned to the “operation” position to continue the operation.

In the present embodiment, when the rotational speed of the engine reaches a predetermined rotational speed (for example, 1200 min ⁻¹ ), the controller 8 outputs an output start signal (PON signal) to the control unit 33, and this PON signal When the control unit 33 receives the signal, the gate of the inverter 32 is turned ON, and the output from the inverter can be started.

  The controller 8 described above may perform a warm-up operation of the engine 21 according to a predetermined condition when the engine 21 is started.

  In the present embodiment, when the controller 8 determines that the engine coolant temperature is lower than the set temperature based on an electrical signal from a coolant temperature sensor (not shown) provided in the engine 21, the controller 8 The ECU 26 is caused to perform a warm-up operation that operates until the cooling water temperature of the engine 21 reaches the set temperature without shifting to a load start mode described later.

In this embodiment, as an example, when the engine coolant temperature detected by the temperature sensor is less than 20 ° C., the engine is uniformly set to 1300 min ⁻¹ regardless of various settings until it reaches 20 ° C. or higher. The warm-up operation is performed by operating at a constant speed.

  In addition, when performing predetermined warm-up operation, the engine can be prevented from being stopped due to load connection by connecting the load after the warm-up of the engine is completed.

  In this embodiment, the breaker 5 provided between the waveform shaping unit 4 and the output terminal block 6 is a circuit between the waveform shaping unit 4 and the output terminal block 6 when the output voltage falls below a predetermined value (about 100 to 110 V as an example). Therefore, the load is not connected to the inverter 32 when the engine is started.

  In this state, after the engine 21 is started, when the temperature of the engine 21 becomes equal to or higher than a predetermined temperature, the warm-up operation is finished, and the controller 8 is connected to the engine speed control line Lc described with reference to FIGS. The engine rotational speed control based on the correspondence relationship between the power consumption on the load side and the engine rotational speed, which is derived based on the above, is started.

  At the end of the warm-up operation, the above-described breaker 5 remains open until an operation by the operator is performed, so that no load is connected to the generator 1. Yes.

  Therefore, the power consumption value on the load side output from the control unit 33 to the controller 8 is also a value indicating that power consumption by the load is not performed (no load state).

  Accordingly, the controller 8 that has received the load-side power consumption value from the control unit 33 reduces the power consumption to zero based on the correspondence relationship stored in the storage means, in the embodiment shown in FIG. A corresponding rotational speed (minimum rotational speed) is set as the target rotational speed, and a command signal is output to the ECU 26 so as to control the fuel supply amount to the engine 21 so that the rotational speed of the engine approaches this target rotational speed.

  From this state, when the operator operates the breaker to connect the load, the load current value detected by the current detecting means 35 changes along with the connection of the load, and the load current value corresponds to the change. Thus, the power consumption value (calculated value) output from the control unit 33 to the controller 8 also increases.

  The controller 8 that has received the increase in the power consumption value sets the rotation speed corresponding to the change in power consumption as the target rotation speed in accordance with the correspondence relationship (rotation speed correspondence table 81) stored in the storage means. A command signal for the ECU 26 is output so as to approach the rotational speed of the engine.

  The control unit 33 constantly monitors the change of the load current via the current detection means 35 and continuously supplies the power consumption value on the load side calculated based on the current value detected by the current detection means 35 to the controller 8. The controller 8 that receives the power consumption value from the control unit 33 and outputs it to the ECU 26 according to the correspondence stored in the storage means so that the rotational speed of the engine 21 approaches the rotational speed corresponding to the received power consumption value. On the other hand, the engine 21 is controlled so that the rotational speed of the engine 21 becomes an optimal rotational speed in accordance with a change in power consumption on the load side.

  The correspondence relationship between the power consumption on the load side and the engine rotational speed stored in the storage means of the controller 8 is the engine rotational speed control line Lc obtained by the method described with reference to FIGS. This rotational speed control line Lc is an approximately smooth line so that the minimum fuel consumption curve Lf at which the fuel consumption of the engine 21 is minimum is lower than the generator output line Lg. Therefore, it is possible to realize low fuel consumption that is close to the case where the engine speed is controlled according to the minimum fuel consumption curve Lf.

  As an example, in comparison with the generator output power of 8 kW, the fuel consumption rate of the constant speed control type engine driven generator was 260 g / kW · hr, whereas the engine driven inverter generator of the present invention The fuel consumption rate has decreased to 240 g / kW · hr, and an improvement of about 7.7% has been obtained.

  In addition, the engine-driven inverter generator according to the present invention that controls the rotational speed of the engine based on the correspondence relationship according to the rotational speed control line Lc of the engine while obtaining the effect of improving the fuel consumption rate. In this case, since the change in the rotational speed with respect to the change in the engine output (power consumption on the load side) becomes smooth, the followability of the engine speed change with respect to the power consumption change on the load side can be improved. Moreover, since the engine speed does not change rapidly, the "noisiness" of the engine sound that is felt by such a change in the engine speed is greatly reduced.

  In addition, since the engine is operated at a rotational speed in which a predetermined margin Δ1 and a power generation loss Δ2 are added to the maximum output, it is aged due to environmental changes (atmospheric pressure, temperature), filter clogging, etc. Even if the engine output decreased due to deterioration, performance changes due to variations in the quality of the fuel used, etc., this decrease could be compensated.

  Furthermore, as described above, since the engine is always operated with a predetermined margin, even if a sudden load fluctuation occurs, the engine output and rotational speed follow the load fluctuation. It is possible to change the speed quickly, and the running load may be stopped due to a temporary shortage of power supply due to a delay in the increase in engine speed with respect to the increase in load, It was possible to suitably prevent malfunctions such as failure of the track and further stalling of the engine.

DESCRIPTION OF SYMBOLS 1 Engine drive type inverter generator 2 Electric power generation part 21 Engine 22 Generator main body 24 Electronic governor 25 Rotational speed sensor 26 Engine control unit (ECU)
DESCRIPTION OF SYMBOLS 3 Power conversion part 31 Converter 32 Inverter 33 Control unit 34 Current detection means 35 Current detection means 4 Waveform shaping part 41 AC reactor 42 Filter capacitor 43 Common mode choke 5 Breaker 6 Output terminal block 7 Input means 71 Frequency change switch 72 Voltage change switch 76 Starter switch 8 Controller 81 Rotational speed correspondence table Lmax Maximum engine output curve Lg Generator output line Lf Minimum fuel consumption curve Le Equivalent fuel efficiency curve Ld Control curve Lc Engine rotational speed control line Δ1 Margin Δ2 Power generation loss

Claims (6)

An engine, a generator main body driven by the engine, a converter that converts alternating current generated in the generator main body into direct current, and an inverter that converts direct current output from the converter into predetermined alternating current and supplies the alternating current to a load In an engine-driven inverter generator that controls the engine speed according to the detected change in power consumption on the load side,
On the engine performance diagram showing the relationship between the engine output and the rotational speed, find one generator output line obtained by subtracting the output of the predetermined margin and power generation loss from the maximum output curve of the engine. Furthermore, based on the equal fuel consumption rate curve shown on this performance diagram and the engine output, the minimum fuel consumption curve is determined by the point that the fuel consumption is minimized for any engine output between 0 and the maximum output. Seeking
When the minimum fuel consumption curve is positioned on the low output side with respect to the generator output line in the entire rotational speed range of the engine, an approximate line obtained by deforming the minimum fuel consumption curve into an approximately smooth line. Is the engine speed control line,
The minimum fuel consumption curve is positioned on the low output side with respect to the generator output line in a part of the rotational speed range of the engine, and the minimum fuel consumption curve overlaps with the generator output line in the other rotational speed range and / or Alternatively, when the generator output line is positioned on the high output side, a connection formed by connecting the minimum fuel consumption curve in the partial rotation speed range and the generator output line in the other rotation speed range. The approximate line obtained by deforming the curve into an approximately smooth line is the engine speed control line,
When the minimum fuel consumption curve overlaps with the generator output line and / or is located on the high output side with respect to the generator output line in the entire rotation speed range of the engine, the generator output line is connected to the engine rotation speed. Control line,
Based on the engine speed control line, an engine speed that generates an output corresponding to the detected power consumption value on the load side is obtained, and the obtained speed is set as the target speed so as to approach the target speed. A method for controlling an engine-driven inverter generator, characterized by controlling the rotational speed of the engine.   2. The control method for an engine-driven inverter generator according to claim 1, wherein the predetermined margin to be subtracted from the maximum output curve is increased on the low engine speed side and decreased on the high engine speed side.   When the predetermined margin subtracted from the maximum output curve causes a maximum load value increase that can occur at the rotational speed in a state where the rotational speed is operating, an output of a predetermined minimum voltage value is generated. 2. The control method for an engine-driven inverter generator according to claim 1, wherein a value capable of maintaining the above is set by experimentally obtaining in advance. An engine, a generator main body driven by the engine, a converter that converts alternating current generated in the generator main body into direct current, and an inverter that converts direct current output from the converter into predetermined alternating current and supplies the alternating current to a load In an engine-driven inverter generator provided with an engine control device for controlling the rotational speed of the engine according to the correspondence stored in advance in the storage means according to the change in power consumption on the load side detected by the power consumption detection means ,
On the engine performance diagram showing the relationship between the engine output and the rotational speed, find one generator output line obtained by subtracting the output of the predetermined margin and power generation loss from the maximum output curve of the engine. Furthermore, based on the equal fuel consumption rate curve shown on this performance diagram and the engine output, the minimum fuel consumption curve is determined by the point that the fuel consumption is minimized for any engine output between 0 and the maximum output. Seeking
When the minimum fuel consumption curve is positioned on the low output side with respect to the generator output line in the entire rotational speed range of the engine, an approximate line obtained by deforming the minimum fuel consumption curve into an approximately smooth line. Is the engine speed control line,
The minimum fuel consumption curve is positioned on the low output side with respect to the generator output line in a part of the rotational speed range of the engine, and the minimum fuel consumption curve overlaps with the generator output line in the other rotational speed range and / or Alternatively, when the generator output line is positioned on the high output side, a connection formed by connecting the minimum fuel consumption curve in the partial rotation speed range and the generator output line in the other rotation speed range. The approximate line obtained by deforming the curve into an approximately smooth line is the engine speed control line,
When the minimum fuel consumption curve overlaps with the generator output line and / or is located on the high output side with respect to the generator output line in the entire rotation speed range of the engine, the generator output line is connected to the engine rotation speed. Control line,
The storage means stores a correspondence relationship between the change in power consumption on the load side obtained based on the engine speed control line and the engine speed that generates an output corresponding to the power consumption value. An engine-driven inverter generator characterized by that.   5. The engine-driven inverter power generation according to claim 4, wherein the predetermined margin to be subtracted from the maximum output curve is obtained by taking a large value on the low engine speed side and a small value on the high engine speed side. Machine.   When the predetermined margin subtracted from the maximum output curve causes a maximum load value increase that can occur at the rotational speed in a state where the rotational speed is operating, an output of a predetermined minimum voltage value is generated. The engine-driven inverter generator according to claim 4, wherein the value is set by experimentally obtaining a value capable of maintaining the above.

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