Engine-driven generator

Abstract

To easily switch a maximum output frequency and a rating voltage of an engine-driven generator so as to be an appropriate combination in accordance with a specification of a connected motor apparatus.SOLUTION: In an inverter 2, an external connection terminal 22 for maximum output frequency setting is provided for setting a maximum output frequency to a first maximum output frequency (58 Hz, for an example) in a first connection state (where terminals 22c and 22a are not connected) and setting the maximum output frequency to a second maximum output frequency (48 Hz, for an example) in a second connection state (where the terminals 22c and 22a are connected). In an automatic voltage regulator (AVR) 43 in a generator body, an external connection terminal 44 for rating output voltage setting is provided for setting a rating voltage to a first rating output voltage (220 V) in a first connection state (where terminals 44c and 44a are connected) and setting the rating output voltage to a second rating output voltage (200 V) in a second connection state (where the terminals 44c and 44b are not connected). The connection states of the external connection terminal 22 in the inverter 2 and the external connection terminal 44 in the AVR can be simultaneously changed over by a changeover switch 5 provided in a control panel 7.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an engine-driven generator, and more particularly to an engine-driven generator with a built-in inverter having a variable output frequency.

Background Art

[0002] A portable engine-driven generator 300 in which an engine 303 and a generator main body 304 driven by the engine 303 are housed in, for example, a common soundproof box 308 is widely used when it is necessary to secure power, particularly outdoors, such as at a construction site or an event venue, due to its portability.

[0003] In such an engine-driven generator 300, as shown in FIG. 10, when a device (load) not shown connected to the engine-driven generator 300 is a device equipped with a three-phase induction motor like a submersible pump (hereinafter, such a device is referred to as a "motor device"), in order to make the output frequency variable for this motor device, the output of the generator main body 304 is input to an inverter 302 via a three-phase output line 351 (351a in the illustrated example), frequency conversion is performed by this inverter 302, and then it is output to a motor device connected to a three-phase output terminal block 361. A device configured in this way has also been proposed (see Claim 3 and FIG. 1 of Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above-described engine-driven generator 300 equipped with the inverter 302, when an operator operates the frequency setting means 321 such as a dial switch provided on the control panel 307 to set the frequency, the inverter 302 converts the output of the generator main body 304 to the set frequency and outputs it, thereby making it possible to vary the rotational speed of the motor device according to the set frequency. As an example, when the above-described motor device is a submersible pump, the submersible pump can be driven at a rotational speed that generates a drainage volume balanced with the amount of water entering the work area, etc., and it becomes possible to control the operation of the motor device according to the situation.

[0006] Here, general-purpose motor devices driven by receiving power supply from a commercial power source include those designed on the premise of operating at 60 Hz / 220 V and those designed on the premise of operating at 50 Hz / 200 V corresponding to the frequency of the commercial power source.

[0007] On the other hand, in the above-described engine-driven generator equipped with an inverter, the maximum value of the frequency (maximum output frequency) that can be changed by the above-described dial switch 321, etc. is generally set corresponding to the higher frequency of 60 Hz so that it can cope with any of the motor devices of the 60 Hz / 220 V and 50 Hz / 200 V specifications described above when connected.

[0008] Therefore, it is possible to increase the output frequency up to a maximum of 60 Hz by operating the above-described dial switch 321, etc. If the motor device connected to the engine-driven generator 300 is a 50 Hz-specification motor device and an output frequency exceeding 50 Hz is accidentally output, an overcurrent will flow through the motor device, leading to a risk of failures such as burnout.

[0009] To address such problems, when a motor device with a 60 Hz specification is connected, the maximum output frequency of the inverter 302 is set to 60 Hz as an example. When a motor device with a 50 Hz specification is connected, the maximum output frequency of the inverter is set to 50 Hz as an example. It is also conceivable to change the setting of the maximum output of the inverter 302 according to the specification of the connected motor device.

[0010] However, in order to change the setting of the maximum output frequency of the inverter 302, it is necessary to expose the inverter 302 by removing a part of the bonnet of the soundproof box 308 and operate the operation panel provided on this inverter 302 to change the setting.

[0011] In addition, since the rated voltage is set to 200 V for motor devices used at a frequency of 50 Hz and 220 V for motor devices used at a frequency of 60 Hz, when changing the setting of the maximum output frequency according to the specification of the connected motor device, it is also necessary to change the setting of the rated output voltage of the generator main body 304 accordingly.

[0012] However, even when changing such a rated output setting, it is necessary to perform operations such as exposing the automatic voltage regulator (AVR) 343 that controls the output voltage of the generator main body 304 by removing a part of the bonnet of the soundproof box 308 and changing the output voltage setting. Performing such operations every time the motor device is replaced is extremely cumbersome.

[0013] Therefore, there is a demand for an engine-driven generator that can relatively easily and accurately change the settings of the maximum output frequency and the rated voltage in the correct combination according to the specification of the connected motor device.

[0014] Therefore, the present invention has been made to solve the drawbacks in the above prior art. In an engine-driven generator incorporating an inverter, according to the specifications of the motor device (three-phase induction motor) to be connected, the settings on the engine-driven generator side can also be easily changed by an extremely simple operation in an appropriate combination without causing setting errors or the like. An object of the present invention is to provide an engine-driven generator that can be changed easily.

Means for Solving the Problems

[0015] Hereinafter, the means for solving the problems will be described together with the reference numerals used in the embodiments for carrying out the invention. This reference numeral is for clarifying the correspondence between the description of the claims and the description of the embodiments for carrying out the invention, and needless to say, it is not used restrictively for interpreting the technical scope of the present invention.

[0016] In order to achieve the above object, the engine-driven generator 1 of the present invention In an engine-driven generator 1 including a generator main body 4, an engine 3 that drives the generator main body 4, a three-phase output terminal block 62 that outputs the electric power generated by the generator main body 4, an inverter 2 provided between the generator main body 4 and the three-phase output terminal block 62 that converts the frequency of the three-phase AC power output by the generator main body 4 and outputs it to the three-phase output terminal block 62, and an automatic voltage regulator (AVR) 43 that controls the output voltage of the generator main body 4, In the inverter 2, the inverter 2 Output power frequency Maximum value is provided with a maximum output frequency setting means 22 (22a to 22d) for setting the setting of the power frequency to a predetermined first maximum output frequency (for example, 58 Hz) or a predetermined second maximum output frequency (for example, 48 Hz), and in the automatic voltage regulator (AVR) 43, a rated output voltage setting means 44 (44a to 44c) for setting the setting of the rated output voltage of the generator main body 4 controlled by the automatic voltage regulator (AVR) 43 to a predetermined first rated output voltage (for example, 220 V) or a predetermined second rated output voltage (for example, 200 V) is provided, The interlocking operation means 5 is provided on the control panel 7 of the engine-driven generator 1 so as to be operable, which operates in conjunction with the maximum output frequency setting means 22 (22a to 22d) and the rated output voltage setting means 44 (44a to 44c). When the maximum output frequency is set to the first maximum output frequency (58 Hz), the rated output voltage is simultaneously set to the first rated output voltage (220 V). When the maximum output frequency is set to the second maximum output frequency (48 Hz), the rated output voltage is simultaneously set to the second rated output voltage (200 V) (see Claims 1: FIGS. 2 to 4).

[0017] In the inverter 2, as the maximum output frequency setting means 22, when a predetermined first connection state (for example, a state where the common terminal 22c and the first input terminal 22a are not connected) is set, the maximum output frequency becomes the first maximum output frequency (58 Hz). When a predetermined second connection state (for example, a state where the common terminal 22c and the first input terminal 22a are connected) is set, the maximum output frequency becomes the second maximum output frequency (48 Hz). An external connection terminal 22 (22a to 22d) for setting the maximum output frequency is provided. In the automatic voltage regulator (AVR) 43, as the rated output voltage setting means 44, when a predetermined first connection state (for example, a state where the common terminal 44c and the first input terminal 44a are connected) is set, the rated output voltage becomes the first rated output voltage (220 V). When a predetermined second connection state (for example, a state where the common terminal 44c and the second input terminal 44b are connected) is set, the rated output voltage becomes the second rated output voltage (200 V). An external connection terminal 44 (44a to 44c) for setting the rated output voltage is provided. The interlocking operation means 5 has contacts (51a to 51c, 52a to 52c) respectively connected to the external connection terminal 22 for setting the maximum output frequency and the external connection terminal 44 for setting the rated output voltage. A first switching position (see FIG. 2(A)) for connecting between the contacts (51a to 51c, 52a to 52c) so that both the external connection terminal 22 for setting the maximum output frequency and the external connection terminal 44 for setting the rated output voltage are in the first connection state. The switching switch 5 may be configured such that both the external connection terminal 22 for setting the maximum output frequency and the external connection terminal 44 for setting the rated output voltage are connected between the contacts (51a to 51c, 52a to 52c) so as to be in the second connection state (see FIG. 2(B)) (see Claims 2: FIGS. 2 to 4).

[0018] Furthermore, an operation unit 57, 57' of the rated rotational speed changing means 56 for changing the rated rotational speed of the engine 3 to the first rated rotational speed (for example, 1800 min -1 ) or the second rated rotational speed (for example, 1500 min -1 ) may be provided on the control panel 7 of the engine-driven generator 1 (see Claims 3: FIGS. 5 to 7).

[0019] When the engine 3 is an electronically controlled engine equipped with an engine control module (ECM) 31, a rated rotational speed setting means 32 (32a to 32c) for switching the setting of the rated rotational speed of the engine 3 to a predetermined first rated rotational speed (1800 min -1 ), or a predetermined second rated rotational speed (1500 min -1 ) is provided in the engine control module (ECM) 31, when the interlocking operation means 5 operates in conjunction with the maximum output frequency setting means 22 and the rated output voltage setting means 44 to set the maximum output frequency to the first maximum output frequency (58 Hz) and the rated output voltage to the first rated output voltage (220 V), the rated rotational speed is simultaneously set to the first rated rotational speed (1800 min -1 ), and when the maximum output frequency is set to the second maximum output frequency (48 Hz) and the rated output voltage is set to the second rated output voltage (200 V), the rated rotational speed can be simultaneously set to the second rated rotational speed (1500 min -1 ) (see Claims 4: FIGS. 3, 4).

[0020] Similarly, when the engine 3 is an electronically controlled engine equipped with an engine control module (ECM) 31, when the engine control module (ECM) 31 is in a predetermined first connection state (for example, a state where the common terminal 32c and the first input terminal 32a are connected), the Of the engine rated rotational speed is set to a predetermined first rated rotational speed (1800 min -1 ), and when the engine control module (ECM) 31 is in a predetermined second connection state (for example, a state where the common terminal 32c and the second input terminal 32b are connected), the rated rotational speed is set to a predetermined second rated rotational speed (1500 min -1 ). A rated rotational speed setting external connection terminal 32 (32a to 32c) is provided, the changeover switch 5 is further provided with contacts (53a to 53c) connected to the rated rotational speed setting external connection terminal 32 (32a to 32c), when the changeover switch 5 is in the first changeover position, the rated rotational speed setting external connection terminal 32 (32a to 32c) is brought into the first connection state, and when the changeover switch 5 is in the second changeover position, the rated rotational speed setting external connection terminal 32 (32a to 32c) is brought into the second connection state. The contacts (53a to 53c) may be connected to each other (see Claim 5: FIGS. 3 and 4).

[0021] Furthermore, A pattern of voltage and frequency changes (V / f constant pattern) that enables a three-phase induction motor to operate at a constant torque even with changes in rotational speed is determined in advance for each of a first base frequency (for example, 60 Hz) and a second base frequency (for example, 50 Hz), which are the base frequencies of the three-phase induction motor (motor device M) connected to the three-phase output terminal block 62. According to the setting of the base frequency in the inverter 2, the inverter 2 is configured to output according to a pattern of voltage and frequency changes corresponding to the set base frequency. when the maximum output frequency setting means 22 provided in the inverter 2 sets the maximum output frequency to the first maximum output frequency (58 Hz), at the same time, the inverter In the sets the base frequency to the first base frequency (for example, 60 Hz), and when the maximum output frequency setting means 22 sets the maximum output frequency to the second maximum output frequency (48 Hz), at the same time, the inverter In the sets the base frequency to the second base frequency (for example, 50 Hz). A base frequency setting function may be added (see Claim 6: FIG. 4).

[0022] In order to realize such a base frequency setting function, the maximum output frequency setting means 22 sets the maximum output frequency to the first maximum output frequency (58 Hz) when the external connection terminals 22 (22a to 22d) for maximum output frequency setting are in the first connection state (for example, a state where the common terminal 22c and the input terminal 22a are not connected), and the inverter 2 In the base frequency Setting of is set to a predetermined first base frequency (60 Hz), and when in the second connection state (for example, a state where the common terminal 22c and the input terminal 22a are connected), the maximum output frequency is set to the second maximum output frequency (48 Hz), and the inverter 2 In the base frequency Setting of is configured to be a predetermined second base frequency (50 Hz) (see Claim 7: Figure 4).

Advantages of the Invention

[0023] With the configuration of the present invention described above, the engine-driven generator 1 of the present invention has achieved the following remarkable effects.

[0024] By providing the interlocking operation means (changeover switch) 5 for simultaneously changing the setting of the maximum output frequency of the inverter 2 and the setting of the rated output voltage of the automatic voltage regulator (AVR) 43 on the control panel 7 of the engine-driven generator 1, by operating the interlocking operation means (changeover switch) 5 provided on the control panel 7, the setting of the maximum output frequency of the inverter 2 and the setting of the rated output voltage of the generator main body 4 can be simultaneously changed and made to be an appropriate combination.

[0025] As a result, by setting the first maximum output frequency to, for example, 58 Hz, the first rated output voltage to, for example, 220 V, the second maximum output frequency to, for example, 48 Hz, and the second rated output voltage to, for example, 200 V, depending on whether the specification of the motor device M connected to the three-phase output terminal block 62 is 60 Hz / 220 V or 50 Hz / 200 V, without removing the bonnet or the like of the soundproof box 8 and directly operating the inverter 2 or the automatic voltage regulator (AVR) 43 to change the settings, by simply operating the interlocking operation means (changeover switch) 5 provided on the control panel 7, the settings on the engine-driven generator 1 side can be easily switched to 58 Hz / 220 V or 48 Hz / 200 V.

[0026] Also, when setting in this way, when the specification of the motor device M connected to the three-phase output terminal block 62 is 50 Hz / 200 V, by selecting the combination of the second maximum output frequency (48 Hz) / the second rated output voltage (200 V) as the maximum output frequency / rated output voltage, even when the frequency setting means 21 constituted by a dial switch or the like is operated to the maximum extent, the output frequency can only be increased up to the second maximum output frequency (48 Hz), and damage to the motor device M can be prevented by preventing the output of a frequency exceeding the specification of the connected motor device M (50 Hz in the above example).

[0027] On the other hand, when the specification of the motor device M connected to the three-phase output terminal block 62 is 60 Hz / 220 V, by selecting the combination of the first maximum output frequency (58 Hz) / the first rated output voltage (220 V) as the maximum output frequency / rated output voltage, the output frequency can be increased up to the second maximum output frequency (58 Hz) by operating the frequency setting means 21 composed of a dial switch or the like to the maximum extent, and the rotational speed can be increased as close as possible to the maximum within the range of the specification of the connected motor device M.

[0028] In the control panel 7 of the engine-driven generator 1, further, the rated rotational speed of the engine 3 is set to the first rated rotational speed (1800 min -1 ), or the second rated rotational speed (1500 min -1) to change, in the configuration provided with the operation units 57 and 57' of the rated rotation speed changing means 56, not only the setting changes of the maximum output frequency and the rated output voltage, but also the setting change of the rated rotation speed of the engine 3 could be easily performed by operating the operation units 57 and 57' provided on the control panel 7.

[0029] Furthermore, when the engine 3 is an electronically controlled engine equipped with an engine control module (ECM) 31, a rated rotation speed setting means 32 (32a to 32c) is provided in this engine control module (ECM) 31, and for this rated rotation speed setting means 32 (32a to 32c) as well, by means of the interlocking operation means (changeover switch) 5 provided on the control panel 7, an operation interlocked with the maximum output frequency setting means 22 and the rated output voltage setting means 44 was enabled. Thus, not only the maximum output frequency of the inverter 2 and the rated output voltage of the generator main body 4, but also the setting of the rated rotation speed of the engine 3 could be simultaneously changed by simply operating the interlocking operation means (changeover switch) 5 provided on the control panel 7.

[0030] Also, by enabling all of these settings to be simultaneously performed by operating the interlocking operation means (changeover switch) 5, it was possible to surely prevent the maximum output frequency, the rated output voltage, and the rated rotation speed from being set in an incorrect combination.

[0031] Furthermore, when the maximum output frequency setting means 22 sets the maximum output frequency to the first maximum output frequency (58 Hz), at the same time the inverter 2 In the sets the base frequency setting to a predetermined first base frequency (60 Hz), and when the maximum output frequency setting means 22 sets the maximum output frequency to the second maximum output frequency (48 Hz), at the same time the inverter 2 In the sets the base frequency setting to a predetermined second base frequency (50 Hz). By adding a base frequency setting function, by performing a so-called "V / f constant control" based on the base frequency and the base frequency voltage corresponding to the specifications of the motor device M connected to the three-phase output terminal block 62, it was possible to operate the motor device M at a constant torque even when the rotation speed was changed.

[0032] In particular, when the external connection terminals 22 (22a to 22d) for setting the maximum output frequency of the maximum output frequency setting means 22 are in a predetermined first connection state (for example, a state where the common terminal 22c and the first input terminal 22a are not connected), the maximum output frequency is set to the first maximum output frequency (58 Hz) and the base frequency is set to the first base frequency (60 Hz). When in a predetermined second connection state (for example, a state where the common terminal 22c and the first input terminal 22a are connected), the maximum output frequency is set to the second maximum output frequency (48 Hz) and the base frequency is set to the second base frequency (50 Hz). By configuring in this way, not only can the setting of the maximum output frequency and the rated output voltage, or the setting of the maximum output frequency, the rated output voltage, and the rated rotational speed of the engine be simultaneously switched by the operation of the interlocking operation means (changeover switch) 5, but also the setting of the base frequency, and thus the change of the output characteristics of the inverter can be simultaneously performed.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiment for Carrying Out the Invention

[0034] Hereinafter, the configuration of the present invention will be described with reference to the accompanying drawings.

[0035] In the following description, by setting the first / second maximum output frequencies of the inverter to frequencies that are lower than the commercial power supply frequencies of 60 Hz / 50 Hz by a predetermined margin, i.e., 58 Hz / 48 Hz, as an example, it is ensured that the output of frequencies exceeding the specifications of the motor device M (usually 60 Hz / 50 Hz) can be reliably prevented. However, the first / second maximum output frequencies can be appropriately set within the range not exceeding the specifications of the connected motor device M (60 Hz / 50 Hz or less). For example, the first / second maximum output frequencies may be set to 60 Hz / 50 Hz corresponding to the specifications of the motor device.

[0036] 〔Overall Configuration of Engine-Driven Generator〕 In FIGS. 1 and 2, reference numeral 1 denotes the engine-driven generator of the present invention. This engine-driven generator 1 accommodates in a soundproof box 8 necessary devices such as an engine 3, a generator main body 4 driven by the engine 3, an output line 61 for extracting the power generated by the generator main body 4, and an inverter 2 for changing the frequency of the power.

[0037] Further, this engine-driven generator 1 is provided with a control panel 7 having switches and instruments for controlling the operations of the engine 3, the generator main body 4, the inverter 2, etc., and a three-phase output terminal block 62 to which a motor device M driven by receiving the power generated by the generator main body 4 is connected, at positions operable from the outside of the aforementioned soundproof box 8.

[0038] 〔Generator Main Body〕 The aforementioned generator main body 4, which is one of the main components of the engine-driven generator 1, can use various known types. In this embodiment, as an example, a self-excited three-phase AC generator equipped with an exciter 42 is used as the generator main body 4 as shown in FIG. 2.

[0039] The generator main body 4 equipped with such an exciter 42 is provided with an automatic voltage regulator (AVR) 43. The output voltage of the main generator 41 is detected by this automatic voltage regulator (AVR) 43, and the detected output voltage of the main generator 41 is compared with a preset reference voltage. When there is an error between the detected output voltage of the main generator 41 and the reference voltage, the excitation current supplied to the exciter 42 is controlled so that the output voltage of the main generator 41 matches the reference voltage.

[0040] Therefore, by changing the setting of the aforementioned reference voltage used in the automatic voltage regulator (AVR) 43, the rated output voltage of the generator main body 4 can be changed.

[0041] In the engine-driven generator 1 of the present invention, a rated output voltage setting means 44 for setting the above-mentioned reference voltage, and thus the rated output voltage of the generator main body 4, to a predetermined first rated output voltage (220V) or a second rated output voltage (200V) is provided in this automatic voltage regulator (AVR) 43.

[0042] In this embodiment, external connection terminals 44 (44a to 44c) for setting the rated output voltage are provided as the rated output voltage setting means 44, and the setting of the rated output voltage can be changed by changing the connection state between these external connection terminals 44 (44a to 44c).

[0043] In the illustrated example, in the first connection state [see Fig. 2(A)] where the common terminal 44c is connected to the first input terminal 44a, a control signal from the common terminal 44c is input to the first input terminal 44a, and the rated output voltage of the generator main body 4 is set to 220V. On the other hand, in the second connection state [see Fig. 2(B)] where the common terminal 44c is connected to the second connection terminal 44b, a control signal from the common terminal 44c is input to the second input terminal 44b, and the rated output voltage of the generator main body 4 is configured to be set to 200V.

[0044] 〔Inverter〕 In the engine-driven generator 1 configured as described above, an output line 61 for extracting the electric power generated by the generator main body 4 is provided, and this output line 61 is connected to a three-phase output terminal block 62 to which a motor device M is connected via an inverter 2 and a breaker 63.

[0045] This inverter 2 has a converter section (not shown) that converts the input power into direct current and an inverter section (not shown) that converts the direct current obtained by the converter section into alternating current of a predetermined frequency and voltage. It is configured to be able to generate an alternating current output of an arbitrary frequency set by an operator by operating frequency setting means 21 such as a dial switch provided on the control panel 7 by a known PWM (pulse width modulation) method or the like.

[0046] Here, there are motor devices M designed on the premise of driving at 60Hz / 220V and those designed on the premise of driving at 50Hz / 200V as described above. If 60Hz / 220V is output to a motor device M designed on the premise of driving at 50Hz / 200V, the motor device M may be damaged.

[0047] Therefore, in the engine-driven generator 1 of the present invention, as shown in FIG. 2, the inverter 2 is provided with maximum output frequency setting means 22 (22a to 22d). By this maximum output frequency setting means 22, the maximum output frequency is selected and set to either the first maximum output frequency (58 Hz) or the second maximum output frequency (48 Hz), and the maximum value of the frequency that can be output to the inverter by the operation of the frequency setting means 21 can be made variable between the first maximum output frequency (58 Hz) and the second maximum output frequency (48 Hz).

[0048] In this embodiment, the maximum output frequency setting means 22 is constituted by external connection terminals 22 (22a to 22d) for maximum output frequency setting. By changing the connection state of these external connection terminals 22 (22a to 22d) for maximum output frequency setting, the setting of the maximum output frequency can be switched between the first maximum output frequency (58 Hz) and the second maximum output frequency (48 Hz).

[0049] In the illustrated embodiment, as the external connection terminals 22 for maximum output frequency setting, a common terminal 22c, a first input terminal 22a that is connected / disconnected from the common terminal 22c, a second input terminal 22b connected to the output frequency setting means 21, and a third input terminal 22d are provided.

[0050] Among these, the second input terminal 22b is invalidated when in the second connection state (see FIG. 2(B)) where the common terminal 22c and the first input terminal 22a are connected, but is validated when in the first connection state (see FIG. 2(A)) where the common terminal 22c and the first input terminal 22a are disconnected, and a control signal corresponding to the operation amount of the frequency setting means 21 is input to a control device (not shown) provided in the inverter from the frequency setting means 21 via the second input terminal 22b.

[0051] Further, the third input terminal 22d is invalidated when in the first connection state [see Fig. 2(A)] where the connection between the common terminal 22c and the first input terminal 22a is interrupted, but is validated when in the second connection state [see Fig. 2(B)] where the common terminal 22c and the first input terminal 22a are connected, and a control signal corresponding to the operation amount of the frequency setting means 21 is configured to be input from the frequency setting means 21 to a control device (not shown) provided in the inverter 2 via the third input terminal 22d.

[0052] In this way, in the state where the second input terminal 22b is validated, that is, in the state where a control device (not shown) provided in the inverter 2 receives a control signal from the frequency setting means 21 via the second input terminal 22b, the control device (not shown) sets the maximum output frequency to the first maximum output frequency (58 Hz), and within the range of this first maximum output frequency (58 Hz), causes the inverter 2 to output at a frequency corresponding to the operation amount of the frequency setting means 21 defined by the received control signal.

[0053] On the other hand, in the state where the third input terminal 22d is validated, that is, in the state where a control device (not shown) provided in the inverter 2 receives a control signal from the frequency setting means 21 via the third input terminal 22d, the control device (not shown) sets the maximum output frequency to the second maximum output frequency (48 Hz), and within the range of this second maximum output frequency (48 Hz), causes the inverter 2 to output at a frequency corresponding to the operation amount of the frequency setting means 21 defined by the received control signal.

[0054] Therefore, by setting the connection state between the common terminal 22c and the first input terminal 22a to the first connection state where the connection is interrupted, the maximum output frequency can be set to the first maximum output frequency (58 Hz), and by setting the connection state between the common terminal 22c and the first input terminal 22a to the second connection state where they are connected and inputting a control signal (contact signal) from the common terminal 22c to the first input terminal 22a, the maximum output frequency can be changed to the second maximum output frequency (48 Hz).

[0055] As a result, in the state where the external connection terminal 22 for maximum output frequency setting is in the first connection state (the connection between 22a and 22c is interrupted), the operator can increase the output frequency of the inverter 2 up to the first maximum output frequency (58 Hz) at most by operating the frequency setting means 21. However, when the external connection terminal 22 is in the second connection state (the connection between 22a and 22c is connected), even if the operator operates the frequency setting means 21 to the maximum extent, the output frequency of the inverter cannot be increased beyond the second maximum output frequency (48 Hz).

[0056] 〔Engine〕 The engine 3 that drives the aforementioned generator main body 4 is configured to be able to operate at a predetermined rated rotational speed so that a predetermined frequency (50 Hz or 60 Hz) can be obtained in the generator main body 4. As an example, in the configuration of this embodiment, when the rated rotational speed of the engine 3 is set to the first rated rotational speed (1800 min -1 ), an output of 60 Hz can be obtained from the generator main body 4, and when the rated rotational speed of the engine 3 is set to the second rated rotational speed (1500 min -1 ), an output of 50 Hz can be obtained from the generator main body 4.

[0057] Therefore, when setting the maximum output frequency of the inverter 2 to the first maximum output frequency (58 Hz), the rated rotational speed of the engine is set to the first rated rotational speed (1800 min -1 ), and when setting the maximum output frequency of the inverter to the second maximum output frequency (48 Hz), it is necessary to set the rated rotational speed of the engine to the second rated rotational speed (1500 min -1 ).

[0058] In order to enable such a change in the setting of the rated rotational speed, the engine-driven generator 1 of the present invention is provided with a rated rotational speed changing means 56, and operation parts 57, 57' of this rated rotational speed changing means 56 are provided on the control panel 7. By operating the operation parts 57, 57' of this rated rotational speed changing means 56 on the control panel 7, the rated rotational speed of the engine 3 can also be changed in terms of setting.

[0059] As the aforementioned engine 3, in the configuration of this embodiment in which a mechanical governor is adopted for the speed control mechanism, as shown in FIG. 6, this rated rotational speed changing means 56 is constituted by an operation unit (operation knob) 57 provided on the control panel 7 and a mechanical link (link cable in the example of FIG. 6) 58 that connects this operation knob 57 and the governor lever 33 of the engine 3, and is configured such that the governor lever 33 of the engine 3 can be operated by the operation knob 57.

[0060] In this embodiment, as shown in the enlarged view in FIG. 6, this operation knob 57 is configured to be able to move forward and backward between a position (idling position) in a state of being pushed into the control panel 7 and a position (operating position) in a pulled-out state, and by rotating the operation knob 57 in the counterclockwise direction at the position (operating position) in the pulled-out state, the rotational speed of the engine becomes high, and by rotating it in the clockwise direction, the tilting position of the governor lever 33 can be adjusted so that the rotational speed of the engine becomes low.

[0061] Therefore, after starting the engine at the position (idling position) with the operation knob 57 pushed in, when the operator pulls out the operation knob 57, the rotational speed of the engine can be increased to the rated rotational speed, and in this state, while looking at the engine speed meter etc. provided on the control panel 7, operate the operation knob 57. When setting the maximum output frequency of the inverter 2 to the first maximum output frequency (58 Hz), rotate the operation knob 57 in the counterclockwise direction so that the rated rotational speed of the engine becomes the first rotational speed (high speed: 1800 min -1 ) (approaches), and when setting the maximum output frequency of the inverter 2 to the second maximum output frequency (48 Hz), rotate the operation knob 57 in the clockwise direction so that the rated rotational speed of the engine becomes the second rotational speed (low speed: 1500 min -1 ) (approaches) and can be changed.

[0062] 〔Interlocking operation means (changeover switch)〕 In the control panel 7 of the engine-driven generator 1 configured as described above, when the rated output voltage setting means 44 provided in the aforementioned automatic voltage regulator (AVR) 43 and the maximum output frequency setting means 22 provided in the inverter 2 are operated in conjunction, when setting the rated output voltage to the first rated output voltage (220 V), the maximum output frequency is set to the first maximum output frequency (58 Hz), and when setting the rated output voltage to the second rated output voltage (200 V), the maximum output frequency is set to the second maximum output frequency (48 Hz). A linkage operation means 5 is provided.

[0063] In this embodiment, as shown in FIGS. 1 to 5, 7, and 8, this linkage operation means is configured by a changeover switch 5.

[0064] In the example shown in FIG. 2, as this changeover switch, a two-pole double-throw switch is used that connects contact point 52c and contact point 52a when contact point 51c and contact point 51b are in communication, and connects contact point 52c and contact point 52b when contact point 51c and contact point 51a are in communication.

[0065] Then, the first input terminal 22a of the external connection terminal 22 for setting the maximum output frequency provided in the inverter 2 is connected to contact point 51a of this changeover switch 5, and the common terminal 22c of the external connection terminal 22 for setting the maximum output frequency is connected to contact point 51c (nothing is connected to contact point 51b). At the same time, the first input terminal 44a of the external connection terminal 44 for setting the rated output voltage provided in the automatic voltage regulator (AVR) is connected to contact point 52a, the second input terminal 44b of the external connection terminal 44 for setting the rated output voltage is connected to contact point 52b, and the common terminal 44c of the external connection terminal 44 for setting the rated output voltage is connected to contact point 52c, respectively.

[0066] Accordingly, when the changeover switch 5 is switched to the first switching position (see Fig. 2(A)), the external connection terminal 22 for setting the maximum output frequency of the inverter 2 assumes a first connection state in which the connection between the common terminal 22c and the first input terminal 22a is interrupted, and the first maximum output frequency (58 Hz) is set as the maximum output frequency. At the same time, the external connection terminal 44 for setting the rated output voltage of the automatic voltage regulator (AVR) 43 assumes a first connection state in which the common terminal 44c and the first input terminal 44a are connected, and the first rated output voltage (220 V) is set as the rated output voltage.

[0067] On the other hand, when the changeover switch 5 is set to the second switching position (see Fig. 2(B)), the external connection terminal 22 for setting the maximum output frequency of the inverter 2 assumes a second connection state in which the common terminal 22c and the first input terminal 22a are connected, and the second maximum output frequency (48 Hz) is set as the maximum output frequency. At the same time, the external connection terminal 44 for setting the rated output voltage of the automatic voltage regulator (AVR) 43 assumes a second connection state in which the common terminal 44c and the second input terminal 44b are connected, and the second rated output voltage (200 V) is set as the rated output voltage.

[0068] 〔Modification Example 1〕 In the embodiment described above, the engine 3 has been described as having a structure with a mechanical governor as a speed control mechanism. However, the engine 3 mounted on the engine-driven generator 1 of the present invention may be an electronically controlled engine provided with an engine control module (ECM) 31, as shown in Fig. 3.

[0069] When such an electronically controlled engine 3 is adopted, a rated rotational speed setting means 32 for setting the rated rotational speed of the engine 3 to either a predetermined first rotational speed (1800 min -1 ), or a predetermined second rotational speed (1500 min -1 ) may be provided in the engine control module (ECM) 31.

[0070] This rated rotational speed setting means 32 may be operable independently, but it is preferably configured to be operable in conjunction with the maximum output frequency setting means 22 provided in the inverter 2 and the rated output voltage setting means 44 provided in the automatic voltage regulator (AVR) by the above-described interlocking operation means (changeover switch) 5.

[0071] In this embodiment, the rated rotational speed setting means 32 provided in the engine control module (ECM) 31 is constituted by the rated rotational speed setting external connection terminals 32 (32a to 32c). In the first connection state where the common terminal 32c of the external connection terminal 32 is connected to the first input terminal 32a, the first rated rotational speed (1800 min -1 ) is set as the rated rotational speed, and in the second connection state where the common terminal 32c is connected to the second input terminal 32b, the second rated rotational speed (1500 min -1 ) is configured to be set as the rated rotational speed.

[0072] As shown in FIG. 7, the change of the connection state of such rated rotational speed setting external connection terminals 32 (32a to 32c) is provided with a switch 57' separately from the changeover switch (interlocking operation means) 5 for setting the maximum output frequency and the rated output voltage described above. The switch 57' and the rated rotational speed setting external connection terminals 32 (32a to 32c) constitute the rated rotational speed changing means 56, and this switch 57' is provided as an operation unit on the control panel 7 of the rated rotational speed changing means 56. By operating this switch 57', the setting of the maximum output frequency and the rated output voltage can be independent, and the setting of the rated rotational speed of the engine 3 can be changed.

[0073] Preferably, as shown in FIG. 3, the changeover switch 5 for setting the maximum output frequency and the rated output voltage described above is a three-pole double-throw type having, in addition to the contacts 51a to 51c and 52a to 52c, further contacts 53a to 53c. The first input terminal 32a of the rated rotational speed setting external connection terminal 32 provided in the engine control module (ECM) 31 is connected to the contact 53a, the second input terminal 32b of the rated rotational speed setting external connection terminal 32 is connected to the contact 53b, and the common terminal 32c of the rated rotational speed setting external connection terminal 32 is connected to the contact 53c, respectively.

[0074] Thereby, when the changeover switch 5 is set to the first switching position (see FIG. 3), the rated rotational speed setting external connection terminal 32 of the engine control module (ECM) 31 is in the first connection state in which the common terminal 32c and the first input terminal 32a are connected, and the first rated rotational speed (high speed: 1800 min -1 ) is set as the rated rotational speed of the engine 3.

[0075] On the other hand, when the changeover switch 5 is set to the second switching position (not shown), the rated rotational speed setting external connection terminal 32 of the engine control module (ECM) 31 is in the second connection state in which the common terminal 32c and the second input terminal 32b are connected, and the second rated rotational speed (1500 min -1 ) is set as the rated rotational speed of the engine.

[0076] As a result, by operating the changeover switch 5, the setting of the maximum output frequency of the inverter 2, the setting of the rated output voltage of the automatic voltage regulator (AVR) 43, and the setting of the rated rotational speed of the engine control module (ECM) 31 can be surely changed simultaneously and in the correct combination.

[0077] Thus, in addition to setting the maximum output frequency of the inverter 2 and the rated output voltage of the automatic voltage regulator (AVR) 43, if the rated rotational speed of the engine control module (ECM) 31 can also be set by a single changeover switch 5, unlike the examples shown in FIGS. 6 and 7, as shown in FIG. 8, it is not necessary to provide switches for setting the rotational speed of the engine 3 on the control panel 7 in addition to the changeover switch 5.

[0078] 〔Modification Example 2〕 In the engine-driven generator 1 described with reference to FIGS. 2 and 3, the maximum output frequency of the inverter 2 can be switched between a first maximum output frequency (58 Hz) and a second maximum output frequency (48 Hz) by operating the changeover switch 5 which is an interlocking operation means.

[0079] On the other hand, in the embodiment shown in FIG. 4, by operating the changeover switch 5, not only can the maximum output frequency of the inverter be switched between a first maximum output frequency (58 Hz) and a second maximum output frequency (48 Hz), but also the inverter 2 In can be switched between a predetermined first base frequency (for example, 60 Hz) and a second base frequency (for example, 50 Hz) in terms of setting the base frequency, which is different.

[0080] Here, as parameters serving as a reference when operating a three-phase induction motor, there are a "base frequency" and a "base frequency voltage".

[0081] This "base frequency" and "base frequency voltage" are the maximum frequency and voltage at which a three-phase induction motor can be continuously operated at rated torque. General-purpose three-phase induction motors are designed such that the base frequency / base frequency voltage is 50 Hz / 200 V or 60 Hz / 220 V corresponding to the frequency of the commercial power supply.

[0082] When changing the output frequency of the inverter 2 to control the rotational speed of the motor device (three-phase induction motor) M, by performing the so-called "V / f constant control" in which the ratio of voltage (V) to frequency (f) remains constant (V / f = constant) even with the change in frequency, it becomes possible to operate the motor device M at a constant torque regardless of the change in rotational speed.

[0083] In such "V / f constant control", the V / f pattern for the motor device M with a base frequency and base frequency voltage of 60 Hz / 220 V becomes, for example, the graph shown by the solid line in Fig. 9, while the V / f pattern for the motor device M with a base frequency and base frequency voltage of 50 Hz / 200 V becomes, for example, the graph shown by the dashed line in Fig. 9. When the base frequency and base frequency voltage of the motor device M are different, the V / f pattern to be applied to obtain constant torque operation changes.

[0084] Here, in the V / f pattern with a base frequency / base frequency voltage of 60 Hz / 220 V (refer to the solid line graph in Fig. 9 for example), since the voltage at the same frequency is lower compared to the V / f pattern with a base frequency / base frequency voltage of 50 Hz / 200 V (refer to the dashed line graph in Fig. 9 for example), when driving the motor device M of 50 Hz / 200 V specification with a V / f pattern of 60 Hz / 220 V for which the base frequency does not correspond, the output torque of the motor device M decreases due to insufficient voltage.

[0085] As a result, even when driving the motor device M at less than the rated output, an overcurrent may occur in the inverter 2 of the engine-driven generator 1, and the output may be cut off, which is called "overcurrent trip", by the protection function of the inverter 2, and thus the work may become impossible.

[0086] In particular, when the motor device M has a low power factor, since it consumes more current even with the same output, an overcurrent is more likely to occur, and the output cut-off due to the aforementioned "overcurrent trip" is even more likely to occur.

[0087] Therefore, when changing the setting of the output frequency of the inverter 2 according to the specifications of the connected motor device M, not only the maximum output frequency described above needs to be changed, but also correspondingly, the setting of the base frequency needs to be changed so that even when the rotational speed of the motor device M is variable, the motor device M can be operated at a constant torque.

[0088] In order to be able to switch the setting of the maximum output frequency and the setting of the base frequency simultaneously, in the engine-driven generator 1 of the present embodiment, when the maximum output frequency setting means 22 provided in the inverter 2 sets the maximum output frequency to the first maximum output frequency (58 Hz), at the same time, the inverter In sets the base frequency to the first base frequency (60 Hz), and when the maximum output frequency setting is set to the second maximum output frequency (48 Hz), at the same time, the base frequency setting function is added to set the base frequency to the second base frequency (50 Hz).

[0089] Specifically, as shown in FIG. 4, a fourth input terminal 22e is further provided in the maximum output frequency setting means (external connection terminal for maximum output frequency setting) 22 provided in the inverter 2. When this fourth input terminal 22e is connected in parallel with the first input terminal 22a and the common terminal 22c is connected to the first input terminal 22a, at the same time, the fourth input terminal 22e is also connected to the common terminal 22c so that the control signal from the common terminal 22c is also input to the fourth input terminal.

[0090] Thereby, the control device (not shown) provided in the inverter 2 is configured such that when there is no input of the control signal to the fourth input terminal 22e, the base frequency is set to the first base frequency (60 Hz), and when there is an input of the control signal to the fourth input terminal 22e, the base frequency is set to the second base frequency (50 Hz), so that the setting of the maximum output frequency and the setting of the base frequency can be switched simultaneously.

[0091] In the embodiment shown in FIG. 4, as a configuration in which a base frequency setting function is added to the maximum output frequency setting means 22 provided in the inverter 2 of the engine-driven generator 1 described with reference to FIG. 3, the maximum output frequency, the base frequency, the rated output voltage, and the rotational speed of the engine are all switched simultaneously by operating a single changeover switch 5.

[0092] On the other hand, as a configuration in which a fourth input terminal 22e is provided in the maximum output frequency setting means 22 provided in the inverter 2 of the engine-driven generator 1 described with reference to FIG. 2, similar to that described with reference to FIG. 4, to add a base frequency setting function, the maximum output frequency, the base frequency, and the rated output voltage can be switched simultaneously, while the rotational speed of the engine 3 may be separately configured to be switched by providing an operation knob 57 (see FIGS. 5 and 6) or a switch 57' (see FIG. 7).

[0093] Also, when changing the setting of the base frequency, other parameters (for example, torque boost amount, acceleration time, deceleration time, etc.) that are preferably changed simultaneously with the base frequency may also be configured to be changed simultaneously.

Description of Reference Numerals

[0094] 1 Engine-driven generator 2 Inverter 21 Frequency setting means (dial switch) 22 Maximum output frequency setting means (external connection terminal for maximum output frequency setting) 22a First input terminal 22b Second input terminal 22c Common terminal 22d Third input terminal 22e Fourth input terminal 3 Engine 31 Engine control module (ECM) 32 Rated rotational speed setting means (external connection terminal for rated rotational speed setting) 32a First input terminal 32b Second input terminal 32c Common Terminal 33 Governor Lever 4 Generator Main Body 41 Main Generator 42 Exciter 43 Automatic Voltage Regulator (AVR) 44 Rated Output Voltage Setting Means (External Connection Terminals for Rated Output Voltage Setting) 44a First Input Terminal 44b Second Input Terminal 44c Common Terminal 5 Interlocking Operation Means (Changeover Switch) 51a~51c, 52a~52c, 53a~53c Contacts 56 Rated Rotation Speed Changing Means 57 Operation Unit (Operation Knob) 57’ Operation Unit (Switch) 58 Link 61 Output Wire 62 Three-Phase Output Terminal Block 63 Breaker 65 Starter Switch 7 Control Panel 8 Soundproof Enclosure 300 Engine-Driven Generator 302 Inverter 303 Engine 304 Generator Main Body 307 Control Panel 308 Soundproof Enclosure 321 Frequency Setting Means (Dial Switch) 343 Automatic Voltage Regulator (AVR) 351(351a, 351b) Three-Phase Output Wire 361 Three-Phase Output Terminal Block

Claims

1. In an engine-driven generator comprising a generator main body, an engine for driving the generator main body, a three-phase output terminal block for outputting the electric power generated by the generator main body, an inverter provided between the generator main body and the three-phase output terminal block for converting the frequency of the three-phase AC power output from the generator main body and outputting it to the three-phase output terminal block, and an automatic voltage regulator for controlling the output voltage of the generator main body, the inverter is provided with a maximum output frequency setting means for setting the maximum value of the output frequency of the inverter to a predetermined first maximum output frequency or a predetermined second maximum output frequency, and the automatic voltage regulator is provided with a rated output voltage setting means for setting the rated output voltage of the generator main body controlled by the automatic voltage regulator to a predetermined first rated output voltage or a predetermined second rated output voltage, a linkage operation means is provided on the control panel of the engine-driven generator, which operates the maximum output frequency setting means and the rated output voltage setting means in linkage, so that when the maximum output frequency is set to the first maximum output frequency, the rated output voltage is simultaneously set to the first rated output voltage, and when the maximum output frequency is set to the second maximum output frequency, the rated output voltage is simultaneously set to the second rated output voltage.

2. The inverter is provided with an external connection terminal for setting the maximum output frequency as the maximum output frequency setting means, which makes the maximum output frequency the first maximum output frequency when in a predetermined first connection state and the second maximum output frequency when in a predetermined second connection state, the automatic voltage regulator is provided with an external connection terminal for setting the rated output voltage as the rated output voltage setting means, which makes the rated output voltage the first rated output voltage when in a predetermined first connection state and the second rated output voltage when in a predetermined second connection state, the linkage operation means has contacts respectively connected to the external connection terminal for setting the maximum output frequency and the external connection terminal for setting the rated output voltage, a first switching position for connecting the contacts so that both the external connection terminal for setting the maximum output frequency and the external connection terminal for setting the rated output voltage are in the first connection state, The engine-driven generator according to claim 1, wherein a changeover switch is provided which has a second switching position for connecting between the contacts so that both the external connection terminal for maximum output frequency setting and the external connection terminal for rated output voltage setting are in the second connection state.

3. On the control panel of the engine-driven generator, The engine-driven generator according to claim 1 or 2, characterized in that an operation unit of a rated rotational speed changing means is provided for changing the rated rotational speed of the engine to a first rated rotational speed or a second rated rotational speed.

4. The engine is an electronically controlled engine equipped with an engine control module, The engine control module is provided with a rated rotational speed setting means for switching the setting of the rated rotational speed of the engine to a predetermined first rated rotational speed or a predetermined second rated rotational speed, When the interlocking operation means operates in conjunction with the maximum output frequency setting means and the rated output voltage setting means to set the maximum output frequency to the first maximum output frequency and the rated output voltage to the first rated output voltage, the rated rotational speed is simultaneously set to the first rated rotational speed, and The engine-driven generator according to claim 1, characterized in that when the maximum output frequency is set to the second maximum output frequency and the rated output voltage is set to the second rated output voltage, the rated rotational speed is simultaneously set to the second rated rotational speed.

5. The engine is an electronically controlled engine equipped with an engine control module, The engine control module is provided with an external connection terminal for rated rotational speed setting for setting the rated rotational speed of the engine to a predetermined first rated rotational speed when in a predetermined first connection state and setting the rated rotational speed to a predetermined second rated rotational speed when in a predetermined second connection state, The changeover switch is further provided with a contact connected to the external connection terminal for rated rotational speed setting, The engine-driven generator according to claim 2, characterized in that when the changeover switch is in the first switching position, the external connection terminal for rated rotational speed setting is in the first connection state, and when the changeover switch is in the second switching position, the contacts are connected so that the external connection terminal for rated rotational speed setting is in the second connection state.

6. A pattern of voltage and frequency changes that enables a three-phase induction motor to operate at a constant torque even with changes in rotational speed is determined in advance for each of a first base frequency and a second base frequency, which are the base frequencies of the three-phase induction motor connected to the three-phase output terminal block. At the same time, the inverter is configured to output according to the pattern of voltage and frequency changes corresponding to the set base frequency in response to the setting of the base frequency in the inverter. The engine-driven generator according to claim 1, wherein the maximum output frequency setting means provided in the inverter is configured such that when the maximum output frequency is set to the first maximum output frequency, the base frequency in the inverter is simultaneously set to a predetermined first base frequency, and when the maximum output frequency is set to the second maximum output frequency, the base frequency in the inverter is simultaneously set to a predetermined second base frequency, and a base frequency setting function is added.

7. A pattern of voltage and frequency changes that enables a three-phase induction motor to operate at a constant torque even with changes in rotational speed is determined in advance for each of a first base frequency and a second base frequency, which are the base frequencies of the three-phase induction motor connected to the three-phase output terminal block. At the same time, the inverter is configured to output according to the pattern of voltage and frequency changes corresponding to the set base frequency in response to the setting of the base frequency in the inverter. The engine-driven generator according to claim 2, wherein when the external connection terminal for setting the maximum output frequency is in the first connection state, the maximum output frequency is set to the first maximum output frequency and the base frequency in the inverter is set to a predetermined first base frequency, and when the external connection terminal for setting the maximum output frequency is in the second connection state, the maximum output frequency is set to the second maximum output frequency and the base frequency in the inverter is set to a predetermined second base frequency.

Images