JP7715596B2 - Engine-driven generator - Google Patents

Description

The present invention relates to an engine-driven generator, and more specifically to an engine-driven generator with a built-in inverter that allows for variable output frequency.

A portable engine-driven generator 300, which houses an engine 303 and a generator main body 304 driven by this engine 303 in a common soundproof box 308, is widely used due to its portability in places where a power source must be secured, such as construction sites and event venues, particularly outdoors.

As shown in Figure 10, when an unillustrated device (load) connected to the engine-driven generator 300 is a device equipped with a three-phase induction motor, such as a submersible pump (hereinafter, such device will be referred to as "motor device"), it has been proposed to make the output frequency of this motor device variable by inputting the output of the generator body 304 to an inverter 302 via a three-phase output line 351 (351a in the illustrated example), converting the frequency in this inverter 302, and then outputting the frequency to the motor device connected to a three-phase output terminal block 361 (see claim 3 and Figure 1 of Patent Document 1).

JP 2012-110098 A

In the aforementioned engine-driven generator 300 equipped with an inverter 302, when the operator sets the frequency by operating the frequency setting means 321, such as a dial switch, provided on the control panel 307, the inverter 302 converts the output of the generator main body 304 to the set frequency and outputs it, making it possible to vary the rotational speed of the motor equipment according to the set frequency.As an example, if the aforementioned motor equipment is a submersible pump, it is possible to control the operation of the motor equipment according to the situation, such as driving the submersible pump at a rotational speed that generates a discharge amount that balances the amount of water entering the work area.

General-purpose motor equipment that is powered by a commercial power supply comes in two types: one designed to operate at 60Hz/220V, which corresponds to the frequency of the commercial power supply, and the other designed to operate at 50Hz/200V.

On the other hand, in the aforementioned engine-driven generator equipped with an inverter, the maximum frequency (maximum output frequency) that can be changed using the aforementioned dial switch 321, etc., is generally set to correspond to the higher frequency of 60 Hz, so that it can accommodate motor equipment with either the aforementioned 60 Hz/220 V or 50 Hz/200 V specifications.

As a result, it is possible to increase the output frequency up to 60 Hz by operating the aforementioned dial switch 321, etc. If the motor equipment connected to the engine-driven generator 300 is a motor equipment designed for 50 Hz and an output frequency exceeding 50 Hz is accidentally output, an overcurrent may flow through the motor equipment, which may result in a failure such as burning.

To address this issue, it is possible to change the maximum output setting of the inverter 302 to match the specifications of the connected motor equipment. For example, if a 60 Hz motor equipment is connected, the maximum output frequency of the inverter 302 may be set to 60 Hz, but if a 50 Hz motor equipment is connected, the maximum output frequency of the inverter may be set to 50 Hz.

However, in order to change the maximum output frequency setting of the inverter 302, it is necessary to expose the inverter 302 by removing part of the hood of the soundproof box 308, and then operate the operation panel provided on the inverter 302 to change the setting.

In addition, the rated voltage for motor equipment used at a frequency of 50 Hz is set to 200 V, and the rated voltage for motor equipment used at a frequency of 60 Hz is set to 220 V. Therefore, when changing the maximum output frequency setting according to the specifications of the connected motor equipment, it is also necessary to change the rated output voltage setting of the generator main body 304.

However, even when changing the rated output setting, it is necessary to remove part of the hood of the soundproof box 308 to expose the automatic voltage regulator (AVR) 343, which controls the output voltage of the generator main body 304, and then change the output voltage setting. Performing such work every time the motor equipment is replaced is extremely cumbersome.

Therefore, there is a demand for an engine-driven generator that allows the maximum output frequency and rated voltage settings to be accurately changed to the correct combination relatively easily, depending on the specifications of the connected motor equipment.

The present invention was conceived to overcome the drawbacks of the above-mentioned conventional technology, and aims to provide an engine-driven generator with a built-in inverter that allows the settings on the engine-driven generator to be easily changed with extremely simple operations to an appropriate combination, without causing setting errors, depending on the specifications of the connected motor (three-phase induction motor).

Below, the means for solving the problems are described along with the reference numerals used in the description of the embodiment of the invention. These reference numerals are intended to clarify the correspondence between the claims and the description of the embodiment of the invention, and needless to say, are not intended to limit the interpretation of the technical scope of the present invention.

In order to achieve the above object, the engine-driven generator 1 of the present invention comprises:
An engine-driven generator 1 includes a generator body 4, an engine 3 that drives the generator body 4, a three-phase output terminal block 62 that outputs power generated by the generator body 4, an inverter 2 that is provided between the generator body 4 and the three-phase output terminal block 62 and converts the frequency of the three-phase AC power output by the generator 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 body 4,
The inverter 2 is provided with maximum output frequency setting means 22 (22a to 22d) for setting the maximum value of the output frequency of the inverter 2 to a predetermined first maximum output frequency (for example, 58 Hz) or a predetermined second maximum output frequency (for example, 48 Hz),
The automatic voltage regulator (AVR) 43 is provided with rated output voltage setting means 44 (44a to 44c) for setting 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, 220V) or a predetermined second rated output voltage (for example, 200V),
An interlocking operation means 5 is operable on the control panel 7 of the engine-driven generator 1, which operates the maximum output frequency setting means 22 (22a to 22d) and the rated output voltage setting means 44 (44a to 44c) in an interlocked manner so that 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), and 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) (claim 1: see Figures 2 to 4).

The inverter 2 is provided with maximum output frequency setting external connection terminals 22 (22a to 22d) as the maximum output frequency setting means 22, which set the maximum output frequency to the first maximum output frequency (58 Hz) when in a predetermined first connection state (for example, a state in which the common terminal 22c and the first input terminal 22a are not connected), and set the maximum output frequency to the second maximum output frequency (48 Hz) when in a predetermined second connection state (for example, a state in which the common terminal 22c and the first input terminal 22a are connected),
The automatic voltage regulator (AVR) 43 is provided with rated output voltage setting external connection terminals 44 (44a to 44c) as the rated output voltage setting means 44, which set the rated output voltage to the first rated output voltage (220V) when in a predetermined first connection state (for example, a state in which the common terminal 44c and the first input terminal 44a are connected), and set the rated output voltage to the second rated output voltage (200V) when in a predetermined second connection state (for example, a state in which the common terminal 44c and the second input terminal 44b are connected),
The interlocking operation means 5,
The external connection terminal 22 for setting the maximum output frequency and the external connection terminal 44 for setting the rated output voltage have contacts (51a to 51c, 52a to 52c) respectively connected to them,
a first switching position (see FIG. 2A) in which the contacts (51a to 51c, 52a to 52c) are connected so that the maximum output frequency setting external connection terminal 22 and the rated output voltage setting external connection terminal 44 are both in the first connection state;
The maximum output frequency setting external connection terminal 22 and the rated output voltage setting external connection terminal 44 may both be configured as a change-over switch 5 having a second change-over position (see FIG. 2B) that connects the contacts (51 a to 51 c, 52 a to 52 c) so as to be in the second connection state (claim 2: see FIGS. 2 to 4).

The control panel 7 of the engine-driven generator 1 may further be provided with an operating unit 57, 57' of a rated rotation speed changing means 56 for changing the rated rotation speed of the engine 3 to a first rated rotation speed (for example, 1800 min ^-1 ) or a second rated rotation speed (for example, 1500 min ^-1 ) (Claim 3: see Figures 5 to 7).

In addition, when the engine 3 is an electronically controlled engine equipped with an engine control module (ECM) 31,
The engine control module (ECM) 31 is provided with rated rotation speed setting means 32 (32a ^{to 32c} ) for switching the setting of the rated rotation speed of the engine 3 between a predetermined first rated rotation speed (1800 min −1 ) and a predetermined second rated rotation speed (1500 min ⁻¹ );
When the interlocking operation means 5 operates the rated rotation speed setting means 32 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), it simultaneously sets the rated rotation speed to the first rated rotation 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 rotation speed can be set to the second rated rotation speed (1500 min ⁻¹ ) at the same time (claim 4: see FIGS. 3 and 4 ).

Similarly, when the engine 3 is an electronically controlled engine equipped with an engine control module (ECM) 31,
The engine control module (ECM) 31 is provided with rated rotation speed setting external connection terminals 32 (32a to 32c) which set the rated rotation speed of the engine to a predetermined first rated rotation speed (1800 min ^-1 ) when the engine is in a predetermined first connection state (for example, a state in which the common terminal 32c and the first input terminal 32a are connected), and which set the rated rotation speed to a predetermined second rated rotation speed (1500 min ^-1 ) when the engine is in a predetermined second connection state (for example, a state in which the common terminal 32c and the second input terminal 32b are connected),
The changeover switch 5 is further provided with contacts (53a to 53c) connected to the rated rotation speed setting external connection terminals 32 (32a to 32c),
The contacts (53a to 53c) may be configured to be connected together so that the rated rotation speed setting external connection terminals 32 (32a to 32c) are in the first connection state when the changeover switch 5 is in the first changeover position, and the rated rotation speed setting external connection terminals 32 (32a to 32c) are in the second connection state when the changeover switch 5 is in the second changeover position (claim 5: see Figures 3 and 4).

Furthermore, a pattern of change in voltage and frequency (constant V/f pattern) that enables the three-phase induction motor to be operated at a constant torque even when the rotation speed changes is determined in advance for each of the first base frequency (for example, 60 Hz) and the second base frequency (for example, 50 Hz), which are the base frequencies of the three-phase induction motor (motor equipment M) connected to the three-phase output terminal block 62, and
In response to the setting of the base frequency in the inverter 2, the inverter 2 is configured to output in accordance with a pattern of change in voltage and frequency corresponding to the set base frequency,
A base frequency setting function may be added to the maximum output frequency setting means 22 provided in the inverter 2, such that when the maximum output frequency is set to the first maximum output frequency (58 Hz), the base frequency in the inverter is simultaneously set to the first base frequency (60 Hz, for example), and when the maximum output frequency is set to the second maximum output frequency (48 Hz), the base frequency in the inverter is simultaneously set to the second base frequency (50 Hz, for example) (claim 6: see FIG. 4).

In order to realize such a base frequency setting function, the maximum output frequency setting means 22 is configured so that when the maximum output frequency setting external connection terminals 22 (22a to 22d) are in the first connection state (for example, a state in which the common terminal 22c and the input terminal 22a are not connected), the maximum output frequency is set to the first maximum output frequency (58 Hz) and the base frequency in the inverter 2 is set to a predetermined first base frequency (60 Hz), and when the maximum output frequency setting means 22 is in the second connection state (for example, a state in which 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 base frequency in the inverter 2 is set to a predetermined second base frequency (50 Hz) (claim 7: see FIG. 4).

The configuration of the present invention described above enables the engine-driven generator 1 of the present invention to achieve the following significant effects:

By providing an interlocking operation means (changeover switch) 5 on the control panel 7 of the engine-driven generator 1, which simultaneously changes the maximum output frequency setting of the inverter 2 and the rated output voltage setting of the automatic voltage regulator (AVR) 43, it is possible to simultaneously change the maximum output frequency setting of the inverter 2 and the rated output voltage setting of the generator main unit 4 to an appropriate combination by operating the interlocking operation means (changeover switch) 5 on the control panel 7.

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 specifications of the motor equipment M connected to the three-phase output terminal block 62 are 60 Hz/220 V or 50 Hz/200 V, the settings on the engine-driven generator 1 side can be easily switched to 58 Hz/220 V or 48 Hz/200 V simply by operating the interlocking operation means (changeover switch) 5 provided on the control panel 7, without having to remove the hood of the soundproof box 8 or directly operate the inverter 2 or automatic voltage regulator (AVR) 43 to change the settings.

Furthermore, when set in this manner, if the specifications of the motor equipment M connected to the three-phase output terminal block 62 are 50Hz/200V, by selecting the combination of second maximum output frequency (48Hz)/second rated output voltage (200V) as the maximum output frequency/rated output voltage, even when the frequency setting means 21, which consists of a dial switch or the like, is operated to its maximum extent, the output frequency can only be increased to the second maximum output frequency (48Hz). Preventing the output of a frequency that exceeds the specifications of the connected motor equipment M (50Hz in the above example) can prevent damage to the motor equipment M.

On the other hand, if the specifications of the motor equipment M connected to the three-phase output terminal block 62 are 60Hz/220V, by selecting the combination of first maximum output frequency (58Hz)/first rated output voltage (220V) as the maximum output frequency/rated output voltage, the output frequency can be increased to the second maximum output frequency (58Hz) by operating the frequency setting means 21, which consists of a dial switch or the like, to the maximum extent, making it possible to increase the rotational speed close to the maximum within the specifications of the connected motor equipment M.

In a configuration in which the control panel 7 of the engine-driven generator 1 is further provided with operation units 57, 57' of a rated rotation speed changing means 56 for changing the rated rotation speed of the engine 3 to the first rated rotation speed (1800 min ^-1 ) or the second rated rotation speed (1500 min ^-1 ), not only can the settings of the maximum output frequency and rated output voltage be changed, but the setting of the rated rotation speed of the engine 3 can also be changed easily by operating the operation units 57, 57' provided on the control panel 7.

Furthermore, if the engine 3 is an electronically controlled engine equipped with an engine control module (ECM) 31, the engine control module (ECM) 31 is provided with a rated rotational speed setting means 32 (32a-32c), and this rated rotational speed setting means 32 (32a-32c) can also be operated in conjunction with the maximum output frequency setting means 22 and the rated output voltage setting means 44 by using an interlocking operation means (changeover switch) 5 provided on the control panel 7. This makes it possible to simultaneously change not only the maximum output frequency of the inverter 2 and the rated output voltage of the generator main body 4, but also the rated rotational speed of the engine 3, simply by operating the interlocking operation means (changeover switch) 5 provided on the control panel 7.

Furthermore, by making it possible to simultaneously perform all of these settings by operating the interlocking operation means (changeover switch) 5, it is possible to reliably prevent the maximum output frequency, rated output voltage, and rated rotation speed from being set in an incorrect combination.

Furthermore, a base frequency setting function is added to the maximum output frequency setting means 22, whereby when the maximum output frequency is set to the first maximum output frequency (58 Hz), the base frequency in the inverter 2 is set to a predetermined first base frequency (60 Hz), and when the maximum output frequency is set to the second maximum output frequency (48 Hz), the base frequency in the inverter 2 is set to a predetermined second base frequency (50 Hz).By performing so-called "constant V/f control" based on the base frequency and base frequency voltage corresponding to the specifications of the motor equipment M connected to the three-phase output terminal block 62, it is possible to operate the motor equipment M at a constant torque even when the rotational speed is changed.

In particular, when the maximum output frequency setting external connection terminals 22 (22a-22d) of the maximum output frequency setting means 22 are in a predetermined first connection state (for example, when the common terminal 22c and the first input terminal 22a are disconnected), the maximum output frequency becomes the first maximum output frequency (58 Hz) and the base frequency becomes the first base frequency (60 Hz). When the maximum output frequency setting means 22 is in a predetermined second connection state (for example, when the common terminal 22c and the first input terminal 22a are connected), the maximum output frequency becomes the second maximum output frequency (48 Hz) and the base frequency becomes the second base frequency (50 Hz). This allows the operation of the interlocking operation means (changeover switch) 5 to simultaneously switch between the maximum output frequency and the rated output voltage, or between the maximum output frequency, the rated output voltage, and the rated engine rotation speed. Furthermore, it also allows the base frequency setting, and therefore the inverter output characteristics, to be changed simultaneously.

1 is an external perspective view of an engine-driven generator according to the present invention; 1A and 1B are schematic diagrams illustrating an engine-driven generator according to the present invention, in which (A) shows a state in which the selector switch is in the first selector position (maximum output frequency 58 Hz/rated output voltage 220 V), and (B) shows a state in which the selector switch is in the second selector position (maximum output frequency 48 Hz/rated output voltage 200 V). FIG. 10 is a schematic explanatory diagram showing a modified example of the engine-driven generator of the present invention. FIG. 10 is an explanatory diagram showing yet another modified example of the engine-driven generator of the present invention. FIG. 2 is an explanatory diagram of an example of the configuration of a control panel. FIG. FIG. 6 is an explanatory diagram of a modification example of a control panel (a modification example of the part surrounded by the dashed line in FIG. 5 ). FIG. 6 is an explanatory diagram of another modified example of the control panel (a modified example of the portion surrounded by the dashed line in FIG. 5 ). FIG. A conventional engine-driven generator (corresponding to FIG. 1 of Patent Document 1).

The configuration of the present invention will be explained below with reference to the attached drawings.

In the following explanation, the inverter's first and second maximum output frequencies are set to 58Hz and 48Hz, respectively, which are frequencies that are a certain margin lower than the commercial power supply frequencies of 60Hz and 50Hz, thereby reliably preventing the output of frequencies that exceed the specifications of the motor equipment M (usually 60Hz and 50Hz). However, the first and second maximum output frequencies can be set appropriately within the range below the specifications of the connected motor equipment M (60Hz and 50Hz or less); for example, the first and second maximum output frequencies may be set to 60Hz and 50Hz corresponding to the motor equipment specifications.

[Overall configuration of engine-driven generator]
In Figures 1 and 2, reference numeral 1 denotes an engine-driven generator of the present invention, and this engine-driven generator 1 has a configuration in which a soundproof box 8 houses 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, an inverter 2 for changing the frequency of the power, and other necessary equipment.

This engine-driven generator 1 also includes a control panel 7 equipped with switches and meters for controlling the operation of the engine 3, generator main body 4, inverter 2, etc., and a three-phase output terminal block 62 to which the motor equipment M, which is driven by the power generated by the generator main body 4, is connected, all of which are located in positions that can be operated from outside the soundproof box 8.

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

The generator main body 4 equipped with such an exciter 42 is provided with an automatic voltage regulator (AVR) 43, which detects the output voltage of the main generator 41 and compares this detected output voltage of the main generator 41 with a preset reference voltage. If 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.

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

In the engine-driven generator 1 of the present invention, the automatic voltage regulator (AVR) 43 is provided with a rated output voltage setting means 44 that sets the aforementioned reference voltage, and therefore the rated output voltage of the generator main body 4, to a predetermined first rated output voltage (220V) or second rated output voltage (200V).

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

In the illustrated example, when the common terminal 44c is connected to the first input terminal 44a in the first connection state (see Figure 2(A)), 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, when the common terminal 44c is connected to the second connection terminal 44b in the second connection state (see Figure 2(B)), 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 set to 200V.

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

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 specified frequency and voltage. It is configured to generate an AC output of any frequency set by the operator by operating a frequency setting means 21, such as a dial switch, provided on the control panel 7, using a known PWM (pulse width modulation) method, etc.

As mentioned above, there are two types of motor equipment M: one designed to be driven at 60Hz/220V, and the other designed to be driven at 50Hz/200V. If 60Hz/220V is output to motor equipment M designed to be driven at 50Hz/200V, there is a risk that motor equipment M will be damaged.

In the engine-driven generator 1 of the present invention, the inverter 2 is provided with a maximum output frequency setting means 22 (22a-22d) as shown in Figure 2. This maximum output frequency setting means 22 selects and sets the maximum output frequency to either the first maximum output frequency (58 Hz) or the second maximum output frequency (48 Hz). By operating the frequency setting means 21, the maximum value of the frequency that can be output by the inverter can be varied between the first maximum output frequency (58 Hz) and the second maximum output frequency (48 Hz).

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

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

Of these, the second input terminal 22b is disabled when the common terminal 22c and the first input terminal 22a are connected in the second connection state (see Figure 2(B)). However, when the common terminal 22c and the first input terminal 22a are disconnected in the first connection state (see Figure 2(A)), the second input terminal 22b is enabled, and a control signal corresponding to the operation amount of the frequency setting means 21 is input from the frequency setting means 21 to a control device (not shown) provided in the inverter via the second input terminal 22b.

The third input terminal 22d is disabled in the first connection state (see Figure 2(A)) in which the common terminal 22c and the first input terminal 22a are disconnected, but is enabled in the second connection state (see Figure 2(B)) in which 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 input from the frequency setting means 21 to a control device (not shown) provided in the inverter 2 via the third input terminal 22d.

In this way, when the second input terminal 22b is enabled, that is, when the control device (not shown) provided in the inverter 2 is receiving 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 causes the inverter 2 to output at a frequency within this first maximum output frequency (58 Hz) that corresponds to the amount of operation of the frequency setting means 21 specified by the received control signal.

On the other hand, when the third input terminal 22d is enabled, that is, when 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 causes the inverter 2 to output at a frequency within the range of this second maximum output frequency (48 Hz) that corresponds to the amount of operation of the frequency setting means 21 specified by the received control signal.

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

As a result, when the maximum output frequency setting external connection terminal 22 is in the first connection state (22a-22c disconnected), the operator can increase the output frequency of the inverter 2 up to the first maximum output frequency (58 Hz) by operating the frequency setting means 21. However, when the external connection terminal 22 is in the second connection state (22a-22c connected), even if the operator operates the frequency setting means 21 to the maximum, the inverter output frequency cannot be increased beyond the second maximum output frequency (48 Hz).

〔engine〕
The engine 3 that drives the 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) is 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 with a frequency of 60 Hz is 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 with a frequency of 50 Hz is obtained from the generator main body 4.

Therefore, when the maximum output frequency of inverter 2 is set to the first maximum output frequency (58 Hz), the rated rotation speed of the engine must be set to the first rated rotation speed (1800 min ^-1 ), and when the maximum output frequency of inverter 2 is set to the second maximum output frequency (48 Hz), the rated rotation speed of the engine must be set to the second rated rotation speed (1500 min ^-1 ).

To enable this setting change of the rated rotational speed, the engine-driven generator 1 of the present invention is provided with a rated rotational speed change means 56, and operation units 57, 57' of this rated rotational speed change means 56 are provided on the control panel 7. By operating the operation units 57, 57' of this rated rotational speed change means 56 on the control panel 7, the rated rotational speed of the engine 3 can also be changed.

In the configuration of this embodiment, in which a mechanical governor is used as the speed-governing mechanism for the engine 3 described above, as shown in Figure 6, the rated rotational speed change means 56 is configured by an operation unit (operation knob) 57 provided on the control panel 7 and a mechanical link (link cable in the example of Figure 6) 58 that connects this operation knob 57 to the governor lever 33 of the engine 3, so that the governor lever 33 of the engine 3 can be operated by the operation knob 57.

In this embodiment, as shown in the enlarged view in Figure 6, the operation knob 57 is configured to be able to move back and forth between a position where it is pushed in toward the control panel 7 (idling position) and a position where it is pulled out (operating position). In the pulled out position (operating position), the tilt position of the governor lever 33 can be adjusted so that rotating the operation knob 57 counterclockwise increases the engine speed, and rotating it clockwise decreases the engine speed.

Therefore, after starting the engine with the operation knob 57 in a pressed-in position (idling position), the operator can pull out the operation knob 57 to increase the engine speed to the rated speed.In this state, the operator can operate the operation knob 57 while watching the engine tachometer, etc., provided on the control panel 7, and if the maximum output frequency of the inverter 2 is to be set to the first maximum output frequency (58 Hz), the operation knob 57 can be rotated counterclockwise to change the engine rated speed to (approach) the first rotational speed (high speed: 1800 min ^-1 ), and if the maximum output frequency of the inverter 2 is to be set to the second maximum output frequency (48 Hz), the operation knob 57 can be rotated clockwise to change the engine rated speed to (approach) the second rotational speed (low speed: 1500 min ^-1 ).

[Interlocking operation means (changeover switch)]
The control panel 7 of the engine-driven generator 1 configured as described above is provided with an interlocking operation means 5 that operates the rated output voltage setting means 44 provided in the automatic voltage regulator (AVR) 43 described above in conjunction with the maximum output frequency setting means 22 provided in the inverter 2, thereby setting the maximum output frequency to the first maximum output frequency (58 Hz) when the rated output voltage is set to the first rated output voltage (220 V), and setting the maximum output frequency to the second maximum output frequency (48 Hz) when the rated output voltage is set to the second rated output voltage (200 V).

In this embodiment, this interlocking operation means is configured as a selector switch 5, as shown in Figures 1 to 5, 7, and 8.

In the example shown in Figure 2, this changeover switch is a double-pole, double-throw switch that connects contacts 52c and 52a when contacts 51c and 51b are connected, and connects contacts 52c and 52b when contacts 51c and 51a are connected.

The first input terminal 22a of the maximum output frequency setting external connection terminal 22 provided on the inverter 2 is connected to contact 51a of this changeover switch 5, and the common terminal 22c of the maximum output frequency setting external connection terminal 22 is connected to contact 51c (nothing is connected to contact 51b). The first input terminal 44a of the rated output voltage setting external connection terminal 44 provided on the automatic voltage regulator (AVR) is connected to contact 52a, the second input terminal 44b of the rated output voltage setting external connection terminal 44 is connected to contact 52b, and the common terminal 44c of the rated output voltage setting external connection terminal 44 is connected to contact 52c.

As a result, when the changeover switch 5 is switched to the first switch position (see Figure 2 (A)), the inverter 2's maximum output frequency setting external connection terminal 22 enters the first connection state in which the connection between the common terminal 22c and the first input terminal 22a is severed, setting the maximum output frequency to the first maximum output frequency (58 Hz). At the same time, the automatic voltage regulator (AVR) 43's rated output voltage setting external connection terminal 44 enters the first connection state in which the common terminal 44c and the first input terminal 44a are connected, setting the rated output voltage to the first rated output voltage (220 V).

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

[Modification 1]
In the embodiment described above, the engine 3 has been described as having a structure equipped with a mechanical governor as a speed-regulating mechanism, but the engine 3 mounted in the engine-driven generator 1 of the present invention may also be an electronically controlled engine equipped with an engine control module (ECM) 31, as shown in FIG. 3.

When such an electronically controlled engine 3 is adopted, the engine control module (ECM) 31 may be provided with a rated rotation speed setting means 32 that sets the rated rotation speed of the engine 3 to either a predetermined first rotation speed (1800 min ^-1 ) or a predetermined second rotation speed (1500 min ^-1 ).

This rated rotation speed setting means 32 may be designed to operate independently, but it is preferable to use the aforementioned interlocking operation means (changeover switch) 5 to operate it 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).

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

As shown in Figure 7, the connection state of the rated speed setting external connection terminals 32 (32a-32c) can be changed by providing a switch 57' separate from the selector switch (interlocking operation means) 5 used to set the maximum output frequency and the rated output voltage. This switch 57' and the rated speed setting external connection terminals 32 (32a-32c) form the rated speed change means 56, and this switch 57' can be configured as an operating unit provided on the control panel 7 of the rated speed change means 56, allowing the rated speed setting of the engine 3 to be changed by operating the switch 57' independently of the maximum output frequency and rated output voltage settings.

As shown in Figure 3, the changeover switch 5 for setting the maximum output frequency and rated output voltage is preferably a three-pole, double-throw type with contacts 53a-53c in addition to contacts 51a-51c and 52a-52c. The first input terminal 32a of the external connection terminal 32 for setting the rated speed provided on the engine control module (ECM) 31 is connected to contact 53a, the second input terminal 32b of the external connection terminal 32 for setting the rated speed is connected to contact 53b, and the common terminal 32c of the external connection terminal 32 for setting the rated speed is connected to contact 53c.

As a result, when the changeover switch 5 is set to the first changeover position (see Figure 3), the external connection terminal 32 for setting the rated rotation speed of the engine control module (ECM) 31 is set to the first connection state in which the common terminal 32c and the first input terminal 32a are connected, and the first rated rotation speed (high speed: 1800 min ^-1 ) is set as the rated rotation speed of the engine 3.

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

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

In this way, if the maximum output frequency of the inverter 2, the rated output voltage of the automatic voltage regulator (AVR) 43, and the rated rotational speed of the engine control module (ECM) 31 can all be set using a single selector switch 5, unlike the examples shown in Figures 6 and 7, there is no need to provide switches for setting the rotational speed of the engine 3 on the control panel 7 in addition to the selector switch 5, as shown in Figure 8.

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

In contrast to this, the embodiment shown in FIG. 4 differs in that not only can the maximum output frequency of the inverter be switched between a first maximum output frequency (58 Hz) or a second maximum output frequency (48 Hz) by operating the changeover switch 5, but also the setting of the base frequency in the inverter 2 can be switched between a predetermined first base frequency (60 Hz, for example) or a second base frequency (50 Hz, for example).

Here, the reference parameters for operating a three-phase induction motor are "base frequency" and "base frequency voltage."

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

When the output frequency of inverter 2 is changed to control the rotational speed of motor equipment (three-phase induction motor) M, so-called "constant V/f control" is performed, which keeps the ratio of voltage (V) to frequency (f) constant (V/f = constant) even when the frequency changes, making it possible to operate motor equipment M at a constant torque even when the rotational speed changes.

In this type of "constant V/f control," the V/f pattern for motor equipment M with a base frequency and base frequency voltage of 60Hz/220V is shown, for example, by the graph indicated by the solid line in Figure 9, while the V/f pattern for motor equipment M with a base frequency and base frequency voltage of 50Hz/200V is shown, for example, by the graph indicated by the dashed line in Figure 9. If the base frequency and base frequency voltage of motor equipment M differ, the V/f pattern that should be applied to achieve constant torque operation will change.

Here, a V/f pattern with a base frequency/base frequency voltage of 60Hz/220V (see the solid line graph in Figure 9 as an example) will have a lower voltage at the same frequency than a V/f pattern with a base frequency/base frequency voltage of 50Hz/200V (see the dashed line graph in Figure 9 as an example). Therefore, if motor equipment M with a 50Hz/200V specification is driven with a V/f pattern with a base frequency of 60Hz/220V, which does not support this, the output torque of motor equipment M will decrease due to insufficient voltage.

As a result, even if the motor equipment M is being driven at less than its rated output, an overcurrent may occur in the inverter 2 of the engine-driven generator 1, and the inverter 2's protective function may shut off the output in a process known as an "overcurrent trip," making it impossible to perform work.

In particular, if the motor equipment M has a low power factor, it will consume more current even with the same output, making it more likely to experience overcurrent, and the output will be shut off due to the aforementioned "overcurrent trip" even more likely to occur.

Therefore, when changing the output frequency setting of the inverter 2 according to the specifications of the connected motor equipment M, it is desirable not only to change the maximum output frequency as described above, but also to change the base frequency setting accordingly, so that the motor equipment M can be operated at a constant torque even when the rotational speed of the motor equipment M is variable.

In order to enable such simultaneous switching between the maximum output frequency setting and the base frequency setting, in the engine-driven generator 1 of this embodiment, a base frequency setting function is added to the maximum output frequency setting means 22 provided in the inverter 2. When the maximum output frequency is set to the first maximum output frequency (58 Hz), the base frequency of the inverter is simultaneously set to the first base frequency (60 Hz), and when the maximum output frequency is set to the second maximum output frequency (48 Hz), the base frequency is simultaneously set to the second base frequency (50 Hz).

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

As a result, the control device (not shown) provided in inverter 2 is configured to set the base frequency to the first base frequency (60 Hz) when no control signal is input to the fourth input terminal 22e, and to set the base frequency to the second base frequency (50 Hz) when a control signal is input to the fourth input terminal 22e, making it possible to simultaneously switch between the maximum output frequency setting and the base frequency setting.

In the embodiment shown in Figure 4, 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 Figure 3, so that the maximum output frequency, base frequency, rated output voltage, and engine rotation speed can all be switched simultaneously by operating a single selector switch 5.

In contrast, the maximum output frequency setting means 22 provided in the inverter 2 of the engine-driven generator 1 described with reference to Figure 2 may be configured with a fourth input terminal 22e to add a base frequency setting function, as described with reference to Figure 4, making it possible to simultaneously switch the maximum output frequency, base frequency, and rated output voltage, while the rotational speed of the engine 3 may be configured to be switched using a separate operation knob 57 (see Figures 5 and 6) or switch 57' (see Figure 7).

In addition, when changing the base frequency setting, it may also be possible to simultaneously change other parameters that are desirable to change at the same time as the base frequency (e.g., torque boost amount, acceleration time, deceleration time, etc.).

1 Engine-driven generator 2 Inverter 21 Frequency setting means (dial switch)
22 Maximum output frequency setting means (external connection terminal for setting maximum output frequency)
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 rotation speed setting means (external connection terminal for setting rated rotation speed)
32a First input terminal 32b Second input terminal 32c Common terminal 33 Governor lever 4 Generator body 41 Main generator 42 Exciter 43 Automatic voltage regulator (AVR)
44 Rated output voltage setting means (external connection terminal for setting rated output voltage)
44a: First input terminal; 44b: Second input terminal; 44c: Common terminal; 5: Interlocking operation means (changeover switch)
51a to 51c, 52a to 52c, 53a to 53c Contacts 56 Rated rotation speed changing means 57 Operation unit (operation knob)
57' Operation unit (switch)
58 Link 61 Output line 62 Three-phase output terminal block 63 Breaker 65 Starter switch 7 Control panel 8 Soundproof box 300 Engine-driven generator 302 Inverter 303 Engine 304 Generator body 307 Control panel 308 Soundproof box 321 Frequency setting means (dial switch)
343 Automatic Voltage Regulator (AVR)
351 (351a, 351b) Three-phase output line 361 Three-phase output terminal block

Claims (7)

An engine-driven generator including a generator body, an engine that drives the generator body, a three-phase output terminal block that outputs power generated by the generator body, an inverter that is provided between the generator body and the three-phase output terminal block and converts the frequency of the three-phase AC power output by the generator body and outputs it to the three-phase output terminal block, and an automatic voltage regulator that controls the output voltage of the generator 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,
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;
an interlocking operation means operable on a control panel of the engine-driven generator for operating the maximum output frequency setting means and the rated output voltage setting means in conjunction with each other, 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. the inverter is provided with a maximum output frequency setting external connection terminal as the maximum output frequency setting means, which sets the maximum output frequency to the first maximum output frequency when in a predetermined first connection state and sets the maximum output frequency to 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 a rated output voltage as the rated output voltage setting means, which sets the rated output voltage to the first rated output voltage when in a predetermined first connection state and sets the rated output voltage to the second rated output voltage when in a predetermined second connection state;
The interlocking operation means,
a contact connected to each of the maximum output frequency setting external connection terminal and the rated output voltage setting external connection terminal;
a first switching position for connecting the contacts so that the maximum output frequency setting external connection terminal and the rated output voltage setting external connection terminal are both in the first connection state;
2. The engine-driven generator according to claim 1, characterized in that the external connection terminal for setting the maximum output frequency and the external connection terminal for setting the rated output voltage are both configured as a change-over switch having a second change-over position that connects the contacts so as to be in the second connection state. The control panel of the engine-driven generator
3. The engine-driven generator according to claim 1, further comprising an operating unit for rated rotation speed changing means for changing the rated rotation speed of the engine to a first rated rotation speed or a second rated rotation speed. The engine is an electronically controlled engine equipped with an engine control module,
the engine control module is provided with a rated rotation speed setting means for switching the setting of the rated rotation speed of the engine between a predetermined first rated rotation speed and a predetermined second rated rotation speed;
When the interlocking operation means interlocks the rated rotation speed setting means 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 interlocking operation means simultaneously sets the rated rotation speed to the first rated rotation speed, and
2. The engine-driven generator according to claim 1, wherein 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. 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 setting a rated rotation speed, which sets the rated rotation speed of the engine to a predetermined first rated rotation speed when the engine is in a predetermined first connection state, and which sets the rated rotation speed to a predetermined second rated rotation speed when the engine is in a predetermined second connection state;
The changeover switch further includes a contact connected to the external connection terminal for setting the rated rotation speed,
3. The engine-driven generator according to claim 2, wherein the contacts are connected so that the external connection terminal for setting the rated rotational speed is in the first connection state when the changeover switch is in the first changeover position, and the external connection terminal for setting the rated rotational speed is in the second connection state when the changeover switch is in the second changeover position. A pattern of change in voltage and frequency that enables the three-phase induction motor to be operated at a constant torque even when the rotational speed changes is determined in advance for each of the first base frequency and the second base frequency, which are base frequencies of the three-phase induction motor connected to the three-phase output terminal block, and
The inverter is configured to output in accordance with a pattern of voltage and frequency changes corresponding to the set base frequency in response to the setting of the base frequency in the inverter,
2. The engine-driven generator according to claim 1, wherein the maximum output frequency setting means provided in the inverter is provided with a base frequency setting function that, when the maximum output frequency is set to the first maximum output frequency, simultaneously sets the base frequency in the inverter to a predetermined first base frequency, and, when the maximum output frequency is set to the second maximum output frequency, simultaneously sets the base frequency in the inverter to a predetermined second base frequency. A pattern of change in voltage and frequency that enables the three-phase induction motor to be operated at a constant torque even when the rotational speed changes is determined in advance for each of the first base frequency and the second base frequency, which are base frequencies of the three-phase induction motor connected to the three-phase output terminal block, and
The inverter is configured to output in accordance with a pattern of voltage and frequency changes corresponding to the set base frequency in response to the setting of the base frequency in the inverter,
3. The engine-driven generator according to claim 2, wherein the maximum output frequency setting external connection terminal, when in the first connection state, sets the maximum output frequency to the first maximum output frequency and sets the base frequency in the inverter to a predetermined first base frequency, and when in the second connection state, sets the maximum output frequency to the second maximum output frequency and sets the base frequency in the inverter to a predetermined second base frequency.