Method for displaying remaining capacity in an AC generator and display device for displaying remaining capacity

Abstract

Accurately calculates and displays the remaining capacity of an AC generator in terms of its active power value [kW]. [Solution] The AC generator 1 is equipped with voltage detection means and current detection means that detect the instantaneous values ​​V and I of the voltage and current of the generator body 2 and transmit them to the controller 70. Based on the received instantaneous values ​​V and I of voltage and current, the controller 70 calculates the active power P [kW] and apparent power S [kVA] used by the generator body 2, and also calculates the ratio of active power P to apparent power S (P / S) as the power factor PF. Then, the rated output of the generator body 2, the rated output Pr ([kVA]), is corrected using this power factor PF to obtain the rated active power Pr active [kW] is calculated, and this rated active power Pr active Subtract the active power used P[kW] from [kW] to obtain the current remaining capacity P of the AC generator 1. remain By calculating [kW], the exact remaining capacity can be determined.

Description

[Technical Field]

[0001] The present invention relates to a method for displaying the remaining capacity of an AC generator and a remaining capacity display device, and more particularly to a method for displaying the current remaining capacity of an AC generator, for use as a reference, for example, when connecting an additional load when a load is already connected, and a remaining capacity display device that implements this remaining capacity display method. [Background technology]

[0002] In construction sites, event venues, and other outdoor locations, when various power-operated work machines, lighting fixtures, video and audio equipment, and other devices (hereinafter simply referred to as "loads") are used, an engine-driven AC generator is used as the power source for such loads. This generator consists of a synchronous generator body and an engine that drives the generator body, both housed in a soundproof enclosure and packaged together.

[0003] As shown in Figure 7, some generator units mounted on such AC generators are configured to selectively output three-phase AC (for example, three-phase 200V AC) when connected in three-phase mode, and single-phase AC (for example, single-phase 200V and single-phase 100V AC) when connected in single-phase mode, by switching the connection of the armature coils V, W, and U from three-phase connection (see Figure 7(A)) to single-phase connection (see Figure 7(B)).

[0004] Furthermore, as shown in Figure 8, in addition to the three-phase windings V, W, and U connected in a Y configuration as armature coils, a predetermined auxiliary winding V' has been added to the generator body 102. This configuration allows for simultaneous output of single-phase AC (for example, single-phase 200V and single-phase 100V) and three-phase AC (for example, three-phase 200V) from a single generator body 102 without changing the connection state of the armature coils, unlike the generator body described with reference to Figure 7.

[0005] In the AC generator 100 equipped with the generator body 102 configured as described above, as shown in Figure 9, a power output system 110 is formed by an output circuit 120 connected to the output sections u, v, w, v' of the generator body 102 and output terminal blocks (151, 152) connected to the output circuit 120. By connecting loads (L1 to L4) to the output terminal blocks (151, 152), the power generated by the generator body 102 can be supplied to the loads (L1 to L4) via the power output system 110.

[0006] In the illustrated example, the output circuit 120 described above is configured with a three-phase output circuit 130 (130U, 130V, 130W) and a single-phase output circuit 140 (140U, 140V', 140W). A three-phase output terminal block 151 is connected to the three-phase output circuit 130 (130U, 130V, 130W), and a single-phase output terminal block 152 is connected to the single-phase output circuit 140 (140U, 140V', 140W), thereby forming a three-phase output system (for example, a three-phase AC 200V output system) and a single-phase output system (for example, single-phase AC 200V and single-phase AC 100V output systems).

[0007] In this way, the connection of loads (L1 to L4) to the output terminal blocks 151 and 152 provided on the power output system 110 can be done by adding loads even if loads are already connected, as long as it is within the range of the rated output of the generator body 102 (hereinafter referred to as "generator rated output"). Such additional load connections can be made, for example, by adding loads to the same output system (for example, by connecting a new 200V three-phase AC load to a 200V three-phase AC output system that already has loads connected), or, in the case of an AC generator 100 equipped with a generator body 102 capable of simultaneous output of three-phase AC and single-phase AC, by adding loads to different power output systems (for example, by adding new loads to the 200V single-phase AC and / or 100V single-phase AC output system when a load is already connected to the 200V three-phase AC output system).

[0008] However, if the load exceeds the generator's rated output, there is a risk that the armature coil in the generator body 102 may burn out due to the occurrence of an overcurrent, or that the AC generator 100 may be shut down in an emergency to avoid such burnout, interrupting the work.

[0009] Therefore, users need to connect additional loads within the remaining capacity, which is calculated by subtracting the power consumption of the connected loads from the generator's rated output.

[0010] However, it is difficult to immediately determine the remaining capacity from the voltmeter and ammeter readings on the AC generator 100, and as a result, it becomes difficult to determine whether or not it is possible to connect the load that is being added.

[0011] Therefore, there is a demand for the AC generator 100 to be able to display the remaining capacity, for example, on the control panel. To meet this demand, an AC generator has been proposed that can supply power using multiple power supply specifications (for example, three-phase AC and single-phase AC) and that can display the remaining capacity for each power supply specification (see Patent Documents 1 and 2 listed below). [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Patent No. 5487797 [Patent Document 2] Japanese Patent Publication No. 2024-31312 [Overview of the project] [Problems that the invention aims to solve]

[0013] The above-mentioned Patent Documents 1 and 2, cited as prior art documents, both display the remaining capacity for each power supply specification. Therefore, the remaining capacity display can be referenced when determining whether or not to connect additional loads for each power supply specification.

[0014] However, in the AC generator described in Patent Document 1 of the above prior art documents, the remaining capacity for each power supply specification is displayed using apparent power value [kVA], which is a different unit from the active power value [kW] that is commonly used to display power consumption on the load side.

[0015] Therefore, in order to accurately determine whether an additional load can be connected, it is necessary to either convert the remaining capacity displayed as apparent power [kVA] to active power [kW] and compare them, or convert the power consumption [kW] of the load displayed as active power [kVA] to apparent power [kVA] and compare them, making it impossible to immediately determine whether an additional load can be connected.

[0016] Furthermore, if a user mistakenly believes that the apparent power value [kVA] used to indicate the remaining capacity of an AC generator and the active power value [kW] used to indicate the power consumption on the load side are common units and connects additional loads, there is a possibility that the connected loads will exceed the generator's rated output. In this case, an overcurrent may occur in the generator itself, causing the emergency stop device to activate to prevent burnout of the armature windings, resulting in an emergency shutdown of the AC generator and potentially cutting off power supply to the connected loads.

[0017] Therefore, it is preferable to indicate the remaining capacity of an AC generator using the active power value [kW], which is commonly used to indicate power consumption on the load side, rather than the apparent power value [kVA].

[0018] Among the prior art documents cited, Patent Document 2 addresses the request to display the remaining capacity of an AC generator using the active power value [kW], which is used to display the power consumption on the load side (paragraph

[0006] of Patent Document 2), and displays the remaining capacity of an AC generator using the active power value [kW] instead of the apparent power value [kVA].

[0019] However, the accuracy of the remaining capacity value [kW] displayed in Patent Document 2 is not guaranteed.

[0020] In other words, Patent Document 2 compares the "remaining active power [kW]" and the "remaining apparent power [kVA]" and displays the smaller value as the "remaining active power [kW]" (Claim 1 of Patent Document 2). However, as will be detailed below, neither the "remaining active power [kW]" nor the "remaining apparent power [kVA]" accurately displays the "remaining capacity of the AC generator [kW]," and therefore it is not possible to display the accurate "remaining active power [kW]."

[0021] Further details are provided below.

[0022] (1) Inaccuracy when the remaining power [kW] of the active power value is used as the remaining capacity [kW]. (1-1) Use of an inaccurate power factor (cosθ) In Patent Document 2, the "remaining power of the active power value [kW]" is calculated by subtracting the "power consumption [kW]" corresponding to the power consumed by the already connected load from the rated output [kW] of the engine.

[0023] In Patent Document 2, this "power consumption [kW]" is determined as the product of the effective value of the voltage between the output terminals and the effective value of the current flowing through the output terminals, multiplied by the power factor cosθ (paragraph

[0036] of Patent Document 2).

[0024] Furthermore, the "power factor cosθ" used to calculate the "power consumption [kW]" is determined by finding the phase difference θ from the periodic change of the voltage detection value and the periodic change of the current detection value, and then finding the power factor cosθ from this phase difference θ (paragraph

[0037] of Patent Document 2).

[0025] Here, the periodic changes in the detected voltage and current are represented by voltage and current waveforms, but the voltage and current waveforms measured by an AC generator are not necessarily clean sine waves and may be distorted.

[0026] On the other hand, the power factor cosθ calculated based on the phase difference θ between the voltage waveform and the current waveform assumes that the voltage and current waveforms are clean sine waves. Therefore, the power factor cosθ obtained from the phase difference θ of distorted voltage and current waveforms is not accurate.

[0027] In particular, under conditions of voltage imbalance or during transient response, voltage and current waveforms are prone to distortion, and significant errors can occur in the calculated power factor cosθ value.

[0028] As a result, if the "power consumption [kW]" is calculated using a power factor cosθ with such a large error, the "power consumption [kW]" will also be inaccurate, and the "remaining active power [kW]" calculated using this "power consumption [kW]" may also be inaccurate.

[0029] (1-2) Inaccuracy of the remaining power [kW] calculated based on the engine's rated output. In Patent Document 2, the active power consumed by the connected load is determined as "power used" [kW] by the method described above, and then this "power used" [kW] is used in the following equation Remaining active power [kW] = Engine rated output [kW] - Power consumption [kW] The remaining power [kW] of the AC generator is calculated using this method.

[0030] In engine-driven generators, an engine with a rated output [kW] that is significantly larger than the generator's rated output [kW] is often used to ensure that the generator itself operates smoothly.

[0031] Therefore, in the case of an AC generator equipped with an engine with a higher output than the generator itself, if an additional load is connected within the range of the "remaining power [kW]" calculated using the method described above, the total power consumption [kW] of the loads may exceed the generator's rated output [kW], even if the total power consumption [kW] of the loads does not exceed the engine's rated output [kW].

[0032] In this manner, if a load exceeding the generator's rated output [kW] is connected, the generator itself will be overloaded, resulting in an overcurrent. This could cause the generator to burn out. Furthermore, if a safety device activates to protect the generator from such burnout and the AC generator is shut down, the power supply to the connected load will also be cut off.

[0033] (2) Inaccuracy of using the remaining capacity of the apparent power value [kVA] as the remaining capacity of the active power value [kW] In Patent Document 2, the smaller of the aforementioned "remaining active power [kW]" and "remaining apparent power capacity (kVA)" is used as the display value for "remaining active power capacity [kW]".

[0034] In other words, the "remaining active power [kW]" and the "remaining apparent power capacity [kVA]" are compared, and if the value of the "remaining apparent power capacity [kVA]" is smaller, the value of the "remaining apparent power capacity [kVA]" is displayed as the remaining capacity [kW] of the AC generator, with only the unit changed to represent the active power value [kW].

[0035] However, the remaining capacity of the active power value [kW] displayed in this way, although the units have been changed, is essentially the remaining capacity of the apparent power value [kVA] and therefore lacks accuracy.

[0036] As a result, when the value of "remaining apparent power capacity [kVA]" is displayed as the remaining active power capacity [kW], even if a load with a power consumption [kW] within the range of the displayed remaining capacity [kW] is added, the total power consumption of the load may exceed the generator's rated output [kW].

[0037] As explained above, although AC generators that can display remaining capacity have been proposed, conventional AC generators, such as those in Patent Document 1, display the remaining capacity using apparent power value [kVA], which is difficult to understand, or those, such as those in Patent Document 2, which display the remaining capacity using active power value [kW], but the value is inaccurate and unreliable, making them difficult for users to use.

[0038] Therefore, the present invention has been made to overcome the drawbacks of the above-mentioned prior art, and aims to provide a method for displaying the remaining capacity of an AC generator and a remaining capacity display device that can accurately calculate and display the remaining capacity in terms of the active power value [kW] of the AC generator. [Means for solving the problem]

[0039] The means for solving the problem are described below, along with the reference numerals used in the embodiments for carrying out the invention. These reference numerals are intended to clarify the correspondence between the claims and the descriptions of the embodiments for carrying out the invention, and needless to say, they are not used restrictively to interpret the technical scope of the present invention.

[0040] To achieve the above objective, the method for displaying remaining capacity in the AC generator 1 of the present invention is as follows: In an AC generator 1 in which a power output system 10 is formed by output terminal blocks 51 and 52 to which loads L1 to L4 can be connected, and output circuits (20U, 20V, 20W; 30U, 30V, 30W; 40U, 40V', 40W) connecting the output terminal blocks 51 and 52 to the output sections u, v, w, v' of the generator body 2, the method for displaying the remaining capacity is as follows: A voltage detection process that sequentially detects the instantaneous value V of the voltage of the generator body 2, A current detection process that sequentially detects the instantaneous value I of the current in the generator body 2, Based on the instantaneous voltage V and the instantaneous current I, a calculation process for calculating the active power P [kW] used by the generator body 2 at the time of detection of the instantaneous voltage V and the instantaneous current I is performed. The effective value V of the voltage calculated based on the instantaneous value V of the aforementioned voltage. rms And the effective value I of the current calculated based on the instantaneous value I of the current. rms Based on this, an apparent power usage calculation process is performed to calculate the apparent power usage S [kVA], which is the power used by the generator body 2 at the apparent power value [kVA] at the time of detection, A power factor calculation process that calculates the ratio (P / S) of the active power used P [kW] and the apparent power used S [kVA] as the power factor PF of the generator body 2 at the time of detection, By correcting the generator rated output Pr ([kVA]), which is the rated output of the generator body 2, using the power factor PF, the rated output of the generator body 2 at the time of detection is obtained as the rated active power Pr active The rated active power calculation process is calculated as [kW], The rated active power Pr active The difference between [kW] and the above-mentioned active power P[kW] (Pr active -P) is the remaining capacity P of the AC generator 1 at the time of detection. remain Calculate as [kW], remaining capacity calculation process, (Claim 1) characterized by including the following.

[0041] The above-mentioned active power P [kW] can be calculated by integrating the product of the instantaneous value V of the voltage and the instantaneous value I of the current and averaging it over one period (Claim 2).

[0042] The calculated remaining capacity P remain The remaining capacity display process can be further included, which displays [kW] on a display means 80 such as a monitor (Claim 3).

[0043] The aforementioned method for displaying remaining capacity further includes, A determination process to determine whether or not it is possible to connect a load that is scheduled to be newly connected, The method may also include a determination result display process that displays the determination result performed in the determination process on the display means 81 (Claim 4).

[0044] This determination process is, From the effective power P [kW] in use to the current value I of the generator main body 2 at the time of detection working A current value calculation process for obtaining [A], From the rated current value Ir [A] of the generator main body 2 to the current value I working [A] is subtracted to obtain the residual current value I remain A residual current value calculation process for calculating [A], Based on the consumption effective power [kW] which is the power consumption at the effective power value of the load scheduled to be newly connected and the power factor, the load current value I which is the current value flowing through the load when the load is connected load A load current value calculation process for calculating [A], The residual current value I remain [A] and the load current value I load [A] are compared, and the load current value I load [A] is such that the load current value I remain [A] is smaller than the residual current value I remain > I load ), It can be made to include a comparison and determination process for determining that the connection of the load scheduled to be newly connected is possible (Claim 5).

[0045] In addition, the detection of the instantaneous value V of the voltage and the instantaneous value I of the current in the voltage detection process and the current detection process can be performed in each phase unit of the generator main body 2 (Claim 6).

[0046] Also, the remaining capacity display device 60 in the AC generator 1 of the present invention Output terminal blocks 51, 52 to which loads L1 to L4 can be connected, and in the remaining capacity display device 60 in the AC generator 1 in which the power output system 10 is formed by output circuits (20U, 20V, 20W; 30U, 30V, 30W; 40U, 40V', 40W) connecting the output terminal blocks 51, 52 and the output parts u, v, w, v' of the generator main body 2, Voltage detection means (61U, 61V, 61W, 61N) for sequentially detecting the instantaneous value V of the voltage of the generator main body 2, Current detection means (62U, 62V, 62W, 62V') for sequentially detecting the instantaneous value I of the current of the generator main body 2, Based on the instantaneous voltage V and the instantaneous current I, a means for calculating the active power P [kW] used by the generator body 2 at the time of detection of the instantaneous voltage V and the instantaneous current I is provided, The effective value V of the voltage calculated based on the instantaneous value V of the aforementioned voltage. rms And the effective value I of the current calculated based on the instantaneous value I of the current. rms Based on the above, an apparent power calculation means 72 calculates the apparent power used S [kVA], which is the power used at the apparent power value [kVA] of the generator body 2 at the time of detection, A power factor calculation means 73 calculates the ratio (P / S) of the active power used P [kW] to the apparent power used S [kVA] as the power factor PF of the generator body 2 at the time of detection, The generator rated output Pr ([kVA]), which is the rated output of the generator body 2 stored in the storage means 75, is corrected using the power factor PF, thereby converting the rated output at the active power value [kW] of the generator body 2 at the time of detection to the rated active power Pr active A rated active power calculation means 74, which calculates the power as [kW], The rated active power Pr active The difference between [kW] and the above-mentioned active power P[kW] (Pr active -P) is the remaining capacity P of the AC generator 1 at the time of detection. remain The remaining capacity is calculated as [kW], by the remaining capacity calculation means 76. (Claim 7) characterized by including the following.

[0047] The means for calculating the active power used 71 can be configured to calculate the active power used P [kW] by integrating the product of the instantaneous value V of the voltage and the instantaneous value I of the current and averaging it over one period (Claim 8).

[0048] Furthermore, the remaining capacity display device 60 of the present invention includes the remaining capacity P remain The system may further include a display means 80 such as a monitor that displays [kW] (Claim 9).

[0049] Furthermore, the remaining capacity display device 60 of the present invention may also include a determination means 78 that determines whether or not it is possible to connect a load that is to be newly connected and displays the determination result on a display means 81 (Claim 10).

[0050] In this case, the determination means 78 is, The current value I of the generator body 2 at the time of detection is derived from the above-mentioned active power P [kW]. working [A] is calculated by the current usage value calculation unit 78a, The rated current value Ir[A] of the generator body 2 stored in the storage means 75 is used to obtain the operating current value I working Subtract [A] to get the remaining current value I remain [A] is calculated by the remaining current value calculation unit 78b, Based on the active power consumption, which is the power consumption of the load to be newly connected, and the power factor, stored in the storage means 75, the load current value I, which is the current value that flows through the load when the load to be newly connected is connected. load The load current value calculation unit 78c that calculates [A], The aforementioned residual current value I remain [A] and the load current value I load [A] is compared with the load current value I load [A] is the remaining current value I remain A comparison and determination unit 78d may be included that determines that connection of the load to be newly connected is possible when the value is smaller than [A] (Claim 11).

[0051] Furthermore, the detection of the instantaneous voltage V and instantaneous current I in the voltage detection means (61U, 61V, 61W, 61N, 61V') and the current detection means (62U, 62V, 62W, 62V') may be performed on a phase-by-phase basis for the generator body 2 (Claim 12). [Effects of the Invention]

[0052] With the configuration of the present invention described above, the remaining capacity display method for the AC generator 1 of the present invention and the remaining capacity display device 60 that implements this method can be obtained, and the following remarkable effects can be obtained.

[0053] In the remaining capacity display method of the present invention, the active power P [kW] used is calculated based on the instantaneous voltage V and instantaneous current I of the generator body 2 (for example, by integrating the product of the instantaneous voltage and current V and I and averaging it over one period), and the effective values ​​of voltage and current V rms ,I rms Based on the ratio (P / S) of the apparent power used S [kVA] calculated based on the above, the power factor PF of the generator body 2 at the time of detection of the instantaneous voltage V and the instantaneous current I was calculated. Unlike the method of determining the power factor (cosθ) based on the phase difference θ between the voltage waveform and the current waveform, assuming that the voltage waveform and the current waveform are sinusoidal (see Patent Document 2 above), it was possible to calculate the accurate power factor PF without being affected by waveform distortion.

[0054] By being able to calculate the power factor PF accurately in this way, the generator's rated output Pr ([kVA]) can be corrected using this power factor PF to obtain the accurate rated active power Pr of the generator body 2 at the time of detection. active [kW] can be calculated, and this accurate rated active power Pr active By subtracting the active power P [kW] used by the generator body 2 at the time of detection from [kW], the remaining capacity P of the AC generator 1 can be determined. remain This could be determined as an active power value [kW], and as an accurate value.

[0055] As a result, this remaining capacity P remain [kW] is displayed numerically or on a meter on a display device 80 such as a monitor, or this remaining capacity P remain By displaying the determination result on a display means 81 such as a monitor, which determines whether or not a newly planned load can be connected based on [kW], the user can easily and accurately determine whether or not a newly planned load can be connected, and the total power consumption of the load [kW] is equal to the rated active power Pr of the generator body 2. active By easily adjusting the current so that it does not exceed a certain limit, it was possible to suppress problems such as the generator body 2 becoming overcurrent and causing the AC generator 1 to make an emergency stop.

[0056] Remaining capacity P remain [kW] is displayed by showing the result of determining whether or not the load to be newly connected can be connected, or remaining capacity P remain When such a determination result is included in the [kW] display, the current value I of the power output system 10 at the time of detection is calculated from the active power P[kW] used. working [A] is determined, and the operating current value I is calculated from the rated current value Ir[A] of the generator body 2. working Subtract [A] to get the remaining current value I remain [A] is calculated, and the load current value I, which is the current value that flows through the load when the load is connected, is calculated from the active power consumption and power factor of the load to be newly connected that is stored in the storage means 75. load [A] is calculated, and the remaining current value I remain [A] and the load current value I load [A] is compared with the load current value I load [A] is the remaining current value I remain A value smaller than [A] (I load remain By determining that the connection of the newly planned load is possible when the power factor of the already connected load is different from that of the newly planned load, it became possible to accurately determine whether or not the new load can be connected.

[0057] Furthermore, in a configuration in which the instantaneous voltage V and instantaneous current I are detected by the voltage detection means 61U, 61V, 61W, 61N, 61V' and the current detection means 62U, 62V, 62W, 62V' for each phase of the generator body 2, the total power and current of the three-phase output system and the single-phase output system can be acquired simultaneously. Compared to the case where the instantaneous voltage and instantaneous current are detected separately for the three-phase output system and the single-phase output system, the number of detection means (detectors) used can be reduced, and the calculation process for calculating the remaining capacity can be performed relatively simply. [Brief explanation of the drawing]

[0058] [Figure 1] An explanatory diagram of an AC generator equipped with a remaining capacity display device according to the present invention. ​ [Figure 2] An explanatory diagram of another AC generator equipped with the remaining capacity display device of the present invention. [Figure 3] Functional block diagram of the remaining capacity display device of the present invention. [Figure 4] Correlation diagram between the rated active power Practive [kV] and power factor PF of the generator body (rated output 45kVA) used in the embodiment. [Figure 5] A graph showing the correspondence between the rated output [kW] of the engine, the rated current value Ir [A] of the generator body, the rated active power Practive [kW] of the generator body, and the active power used P [kW] in the embodiment. [Figure 6] An explanatory diagram showing an example of how the judgment result is displayed in the display means. [Figure 7] This is a diagram illustrating a conventional generator capable of selectively outputting three-phase AC and single-phase AC, with (A) showing a three-phase connection and (B) showing a single-phase connection. [Figure 8] A diagram illustrating a conventional generator capable of simultaneous output of single-phase and three-phase AC. [Figure 9] Diagram illustrating an AC generator. [Modes for carrying out the invention]

[0059] The configuration of the remaining capacity display device 60 in the AC generator 1 of the present invention will be described below with reference to the attached drawings.

[0060] In the following description, we will use the case where the remaining capacity display device 60 of the present invention is applied to an AC generator 1 that is capable of simultaneous output of three-phase AC and single-phase AC as an example. However, the remaining capacity display device 60 of the present invention may also be applied to an AC generator that can output either three-phase AC or single-phase AC when selected, or to an AC generator that can output only three-phase AC.

[0061] [Overall configuration of the AC generator] Figure 1 shows an example of an AC generator 1 equipped with the remaining capacity display device 60 of the present invention, which enables simultaneous output of three-phase AC and single-phase AC.

[0062] This AC generator 1 comprises a generator body 2 which is a synchronous generator, output circuits (20U, 20V, 20W, 20V'; 30U, 30V, 30W; 40U, 40V', 40W) connected to the output sections u, v, w, v' of the generator body 2, and output terminal blocks 51 and 52 connected to the output circuits. The aforementioned output circuits and output terminal blocks 51 and 52 form the power output system 10 of the AC generator 1, and it is configured to supply power generated by the generator body 2 to loads L1 to L4 connected to the output terminal blocks 51 and 52 via this power output system 10.

[0063] The AC generator 1 shown in Figure 1 employs a generator body 2, which is capable of simultaneously outputting three-phase AC and single-phase AC, as explained with reference to Figure 8. This generator body 2 is equipped with three-phase windings V, W, U connected in a Y configuration with a 120° phase difference around the neutral point N, and an auxiliary winding V' connected to the three-phase windings V, W, U.

[0064] This auxiliary winding V' is connected to the neutral point N to generate an induced voltage that is half the vector sum of the induced voltage of the V-phase winding and has a phase difference of 180°. As a result, a predetermined voltage (200V at 50Hz and 220V at 60Hz in this embodiment) of three-phase AC is obtained from the output terminals v, w, and u provided at the respective ends of the three-phase windings V, W, and U. In the illustrated example, the output terminal u provided at the end of the U winding and the output terminal v' provided at the end of the auxiliary winding V' are connected. Alternatively, a single-phase AC voltage of half the predetermined voltage of the three-phase AC (100V at 50Hz and 110V at 60Hz in this embodiment) is obtained between the output terminal w provided at the end of the W winding and the output terminal v' provided at the end of the auxiliary winding V', and a single-phase AC voltage of the same voltage as the three-phase AC (200V at 50Hz and 220V at 60Hz in this embodiment) is obtained between the output terminal u provided at the end of the U winding and the output terminal w provided at the end of the W winding.

[0065] The frequency of the AC output by the generator body 2 (50Hz or 60Hz) can be switched by changing the rotational speed of the generator body 2 in accordance with the change in the rotational speed of the engine (not shown). However, the following explanation assumes that the AC generator 1 is used to obtain a 60Hz output.

[0066] Therefore, in the illustrated example, the combination of output terminals v, w, and u of the generator body 2 constitutes the three-phase output section (three-phase 220V output section) of the generator body 2, the combination of output terminals u and w constitutes the single-phase output section (single-phase 220V output section) of the generator body 2, and the combinations of output terminals u, v' and w, v' constitute the single-phase output section (single-phase 110V output section) of the generator body 2 at half voltage.

[0067] In this embodiment, the output circuit described above is composed of a main output circuit 20U, 20V, 20W, 20V' connected to the output sections u, v, w, n of the generator body 2, a three-phase output circuit 30U, 30V, 30W connected to 20U, 20V, 20W of the main output circuit, and a single-phase output circuit 40U, 40V', 40W connected to 20U, 20W, 20V' of the main output circuit.

[0068] Then, the three-phase output terminal block 51 is connected to the three-phase output circuits 30U, 30V, and 30W, and the single-phase output terminal block 52 is connected to the single-phase output circuits 40U, 40V', and 40W.

[0069] Therefore, a three-phase power output system is formed by the 20U, 20V, and 20W main output circuits, the three-phase output circuits 30U, 30V, and 30W, and the three-phase output terminal block 51, while a single-phase power output system is formed by the 20U, 20W, and 20V' main output circuits, the single-phase output circuits 40U, 40V', and 40W, and the single-phase output terminal block 52.

[0070] In the illustrated embodiment, the three-phase output circuits 30U, 30V, and 30W are connected to the main output circuits 20U, 20V, and 20W via a three-phase circuit breaker 31, while the single-phase output circuits 40U, 40V', and 40W are connected to the main output circuits 20U, 20V', and 20W via a single-phase circuit breaker 41. This allows the three-phase circuit breaker 31 and the single-phase circuit breaker 41 to be operated to start and stop the power supply to the three-phase load L1 and the single-phase loads L2 to L4.

[0071] [Remaining capacity display device] (1) Overall configuration of the remaining capacity display device The remaining capacity display device 60 of the present invention, mounted on the AC generator 1 configured as described above, includes, as shown in Figure 1, voltage detection means 61U, 61V, 61W, 61V', 61N) for detecting the instantaneous value V of the voltage of the generator body 2, and current detection means 62U, 62V, 62W, 62V' for detecting the instantaneous value I of the current. Based on the instantaneous values ​​V and I of voltage and current detected by the voltage detection means 61U, 61V, 61W, 61V', 61N and the current detection means 62U, 62V, 62W, 62V', the remaining capacity P of the generator body 2 is displayed according to a pre-stored program. remain A control device (controller) 70 consisting of a microcontroller or the like that calculates [kW], and the remaining capacity P calculated by the control device (controller) 70. remain It is equipped with a display means 80, such as a monitor screen, that displays [kW].

[0072] (2) Voltage detection means and current detection means The aforementioned voltage detection means 61U, 61V, 61W, 61V', and 61N perform a voltage detection process that sequentially detects the instantaneous value V of the voltage of the generator body 2, and outputs the detected voltage to the controller 70.

[0073] Furthermore, the aforementioned current detection means 62U, 62V, 62W, and 62V' perform a current detection process that sequentially detects the instantaneous value I of the current in the generator body 2, and outputs the detected instantaneous value I of the current to the controller 70.

[0074] In the remaining capacity display device 60 of this embodiment, a voltage detector 61N is provided as a voltage detection means (voltage detector) connected to the neutral point N of the generator body 2, and voltage detectors 61U, 61V, 61W, and 61V' are provided for each of the main output circuits 20U, 20V, 20W, and 20V' connected to the output sections v, w, u, and n of the generator body 2, thereby enabling the detection of the instantaneous value V of the voltage V (potential difference with the neutral point N) of the U phase, V phase, W phase, and auxiliary winding V' of the generator body 2. In addition, current detectors 62U, 62V, 62W, and 62V', which are current detection means, are provided for each of the main output circuits 20U, 20V, 20W, and 20V', thereby enabling the detection of the instantaneous value I of the current of each phase of the generator body 2.

[0075] In the configuration of the AC generator 1 shown in Figure 1, the voltage detectors 61U, 61V, 61W, 61V' and the current detectors 62U, 62V, 62W, 62V' are all located on the main output circuits 20U, 20V, 20W, 20V'. However, the placement of the voltage detectors 61U, 61V, 61W, 61V' and the current detectors 62U, 62V, 62W, 62V' is not limited to the positions shown in Figure 1, as long as they can measure the instantaneous voltage V and instantaneous current I of the U-phase, V-phase, W-phase and auxiliary winding V' of the generator body 2.

[0076] As an example, in the embodiment shown in Figure 2, intermediate taps u2 and w2 are provided on the U winding and W winding of the generator body 2, respectively. These intermediate taps u2 and w2 are connected to a tap n provided at the neutral point N, and this configuration allows single-phase AC to be extracted. As a result, even if current is detected on the main output circuit 20U, 20W side, it is not possible to measure the sum of the currents output by the U phase and W phase (the sum of the single-phase output current and the three-phase output current).

[0077] Therefore, in the configuration of the AC generator 1 shown in Figure 2, the voltage detection means 61U, 61V, 61W, and 61N are provided on the main output circuits 20U, 20V, 20W, and 20N, while the current detection means 62U, 62V, and 62W are provided on the windings U, V, and W of each phase of the generator body 2, so that the currents of the U, V, and W phases of the generator body 2 (the sum of the single-phase output current and the three-phase output current) can be detected.

[0078] In the following explanation, we will use the configuration of AC generator 1 shown in Figure 1 as a basis, and the configuration of AC generator 1 shown in Figure 2 will only be mentioned when necessary.

[0079] (3) Controller The instantaneous voltage and current values ​​V and I detected by the aforementioned voltage detection means 61U, 61V, 61W, 61V', 61N and current detection means 62U, 62V, 62W, 62V' are sequentially output to the controller 70. Upon receiving the instantaneous voltage and current values ​​V and I, the controller 70 activates the following means according to a pre-stored program to control the remaining capacity P of the AC generator 1. remain Calculate [kW].

[0080] (3-1) Means for calculating available power The active power calculation means 71 performs an active power calculation process to calculate the active power P [kW] based on the instantaneous voltage V detected by the voltage detection means 61U, 61V, 61W, 61V', 61N and the instantaneous current I detected by the current detection means 62U, 62V, 62W, 62V'.

[0081] This active power P [kW] represents the power used by the generator body 2 (power used by loads connected to the generator body 2, etc.) at the time of detection of the instantaneous voltage V and the instantaneous current I, expressed as an active power value [kW]. If a load is connected to the power output system 10, it corresponds to the power consumption of the load.

[0082] The active power used P [kW] can be calculated by integrating the product (V·I) of the instantaneous voltage V detected by the voltage detection means 61U, 61V, 61W, 61V', 61N and the instantaneous current I detected by the current detection means 62U, 62V, 62W, 62V', and averaging it over one period.

[0083] The active power calculation means 71 calculates the instantaneous values ​​(V) of the U-phase voltage and current detected by the voltage detection means 61U, 61N and the current detection means 62U. U ,I U ), the instantaneous values ​​of the V-phase voltage and current detected by the voltage detection means 61V, 61N and the current detection means 62V (V V ,I V ), the instantaneous values ​​of the W-phase voltage and current detected by the voltage detection means 61W, 61N and the current detection means 62W (V W ,I W ), and the instantaneous values ​​(V) of the voltage and current of the auxiliary winding V' detected by the voltage detection means 61V', 61N and the current detection means 62V'. V’ ,I V’ Based on this, the active power P used in the U phase U V-phase active power P V W-phase active power P W , and the effective power P of the auxiliary winding V' V’ Each of these is calculated using the following formula, and the resulting active power used by each phase (P U ,P V ,P W ) and the effective power P of the auxiliary winding V' V’ The total effective power P used by the entire generator unit 2 is calculated by summing these values.

[0084]

number

[0085] Furthermore, if the generator body 2 does not have an auxiliary winding V' as shown in Figure 2, the total usable active power P of the generator body 2 is given by the following equation: P=P U +P V +P W It can be determined by this method.

[0086] (3-2) Use apparent power calculation means The apparent power calculation means 72 calculates the effective value V of the voltage based on the instantaneous value V of the voltage detected by the voltage detection means 61U, 61V, 61W, 61V', 61N, rms and calculates the effective value I of the current based on the instantaneous value I of the current detected by the current detection means 62U, 62V, 62W, 62V'. rms Then, based on the calculated effective value V of the voltage rms and the effective value I of the current rms it executes an apparent power calculation process to calculate the apparent power S [kVA] representing the power consumption of the generator main body 2 at the time of detecting the instantaneous value V of the voltage and the instantaneous value I of the current in terms of apparent power value [kVA].

[0087] The apparent power calculation means 72 calculates, as the root mean square (RMS) over one cycle of the instantaneous values V (V U , V V , V W , V V’ ) of the voltages of each of the U, V, W phases and the auxiliary winding V' detected by the voltage detection means 61U, 61V, 61W, 61V', 61N, the effective value V rms-U of the voltage of the U phase, the effective value V rms-V of the voltage of the V phase, the effective value V rms-W of the voltage of the W phase, and the effective value V rms-V’ of the voltage of the auxiliary winding V' respectively by the following formula,

Equation

[0088] Also, the apparent power calculation means 72 calculates, as the root mean square (RMS) over one cycle of the instantaneous values I (I U , I V , I W , I V’ ) of the currents of each phase detected by the current detection means 62U, 62V, 62W, 62V', the effective value I rms-U of the current of the U phase, the effective value I rms-V, the effective value I of the current in the W phase rms-W , and the effective value I of the current in the auxiliary winding V’ rms-V’ are calculated by the following equations respectively,

Equation

[0089] Then, the apparent power calculation means 72 calculates the apparent power S of the U phase, the apparent power S of the V phase, the apparent power S of the W phase, and the apparent power S of the auxiliary winding V’ based on the effective values of the voltage and current of the U phase (V rms-U , I rms-U ), the effective values of the voltage and current of the V phase (V rms-V , I rms-V ), the effective values of the voltage and current of the W phase (V rms-W , I rms-W ), and the effective values of the voltage and current of the auxiliary winding V’ (V rms-V’ , I rms-V’ ). The apparent power S of the U phase, the apparent power S of the V phase, the apparent power S of the W phase, and the apparent power S of the auxiliary winding V’ are obtained by the following equations respectively, and the total apparent power S of the entire generator body is calculated by adding the obtained apparent powers of each phase and the auxiliary winding V’ (S U , S V , S W , and S V’ ). S U = V V × I W S V’ = V U × I rms-U S rms-U = V V × I rms-V S rms-V = V W × I rms-W S rms-W = V V’ × I rms-V’ S = S rms-V’ U + S V + S W + S V’

[0090] ​Furthermore, if the generator body 2 does not have an auxiliary winding V' as shown in Figure 2, the apparent power S used by the entire generator body 2 is given by the following equation: S=S U +S V +S W It can be determined by this method.

[0091] (3-3) Power factor calculation means The power factor calculation means 73 performs a power factor calculation process in which it calculates the power factor PF (PF=P / S) at the time of detection of the instantaneous voltage and instantaneous current values ​​of the generator body 2, by taking the ratio (P / S) of the active power P [kW] used by the active power calculation means 71 and the apparent power S [kVA] used by the apparent power calculation means 72 as the ratio.

[0092] The power factor PF calculated in this manner represents the power factor of the connected load (or the total power factor if multiple loads are connected) when a load is connected to the output terminal blocks 51 and 52.

[0093] In this embodiment, the power factor is defined as the power factor PF of the entire generator body 2 and the power factor (PF) of each phase. U ,PF V ,PF W ) are calculated separately.

[0094] The power factor PF of the entire generator body 2 is the ratio of the active power P [kW] of the entire generator body 2 calculated by the active power calculation means 71 to the apparent power S [kVA] of the entire generator body 2 calculated by the apparent power calculation means 72, i.e., the following equation PF = P / S It can be determined by this method.

[0095] Furthermore, the power factor PF of the U-phase of the generator body 2 U , power factor PF of the V phase V Power factor PF of the W phase W This is the U-phase active power P calculated by the active power calculation means 71. U V-phase active power P V, and the active power P used in the W phase W [kW] and the apparent power S of the U phase calculated by the apparent power calculation means 72. U , Apparent power used in V phase S V , and the apparent power S used for the W phase W Using [kVA], the following formula PF U =P U / S U PF V =P V / S V , PF W =P W / S W It can be calculated by [method].

[0096] (3-4) Means for calculating rated active power The rated active power calculation means 74 corrects the generator rated output Pr, which is previously stored in the storage means 75 as, for example, apparent power value [kVA], to correspond to the power factor PF at the time of detection calculated by the power factor calculation means 73, thereby calculating the rated active power Pr. active The process of calculating rated active power, which calculates [kW], is executed.

[0097] At one site, rated active power Pr active [kW] is the rated active power Pr of the entire generator unit 2. active of Pr active =Pr×PF It can be calculated by, Rated active power (Pr) of each phase (U phase, V phase, W phase) U active ,Pr V active ,Pr W active ) and the power factor PF of the U phase U , power factor PF of the V phase V Power factor PF of the W phase W Using, Pr U active =(Pr / 3)×PF U Pr V active =(Pr / 3)×PF V Pr W active=(Pr / 3)×PF W It can be calculated as follows.

[0098] The rated active power Pr of the entire generator body 2 calculated by the rated active power calculation means 74 active For example, the calculation of [kW] may be done by storing the generator rated output Pr as an apparent power value [kVA] in the storage means 75, and then simply calculating it as the product of this generator rated output Pr and the power factor PF of the entire generator body 2 calculated by the power factor calculation means 73, as in the embodiment described above.

[0099] However, in this embodiment, as shown in Figure 4, if the power factor PF of the entire generator body 2 calculated by the power factor calculation means 73 is less than 0.8, the rated output Pr [kVA] of the generator is multiplied directly by the power factor PF calculated by the power factor calculation means 73 to obtain the rated active power Pr active The power factor [kW] is calculated, but if the power factor PF calculated by the power factor calculation means 73 is 0.8 or higher, the rated output Pr [kVA] of the generator is uniformly multiplied by 0.8 to obtain the rated active power Pr active [kW] is being calculated.

[0100] This configuration was adopted because the remaining capacity display device 60 of this embodiment is applied to an AC generator 1 in which a generator body 2 with a generator rated output Pr of 45 kVA is driven by an engine with a rated output of 42.5 kW, and as shown in Figure 5, the rated active power Pr of the entire generator body 2 active To ensure that the [kW] does not exceed the engine's rated output (42.5kW) and caps out at 36[kW], the rated current value Ir is lowered to maintain a constant power factor PF of 0.8 when the power factor PF is 0.8 or higher.

[0101] With this configuration, the remaining capacity P calculated by the remaining capacity calculation means 76 described later is remain By connecting a new load within the specified range, the rated active power Pr of the generator unit 2 will increase. active This not only prevents the connected load from exceeding [kW], but also prevents the connected load from exceeding the engine's rated output (42.5kW).

[0102] However, for AC generators where the engine's rated output [kW] is sufficiently large compared to the value obtained by multiplying the generator's rated output Pr [kVA] by a power factor of "1", there is no need to set such an upper limit on the power factor PF.

[0103] (3-5) Remaining capacity calculation method The remaining capacity calculation means 76 calculates the rated active power Pr of the generator body 2 calculated by the rated active power calculation means 74. active Using the [kW] and the active power P [kW] of the generator body 2 calculated by the active power calculation means 71, the remaining capacity P of the generator body 2 at the time of detection is calculated. remain The remaining capacity calculation process is executed to calculate [kW].

[0104] In calculating the remaining capacity of the entire generator body 2, the remaining capacity calculation means 76 calculates the rated active power Pr of the U phase calculated by the rated active power calculation means 74. U active [kW], V-phase rated active power Pr V active [kW] and the rated active power Pr of the W phase W active [kW] and the U-phase active power P calculated by the active power calculation means 71. U [kW], V-phase active power P V [kW] and the active power P used for the W phase. W Using [kW], the remaining capacity P of the U phase U-remain V-phase remaining capacity P V-remain , and the remaining capacity P of the W phase W-remain The following equations apply to each of them. P U-remain =Pr U active -P U P V-remain =Pr V active -P V P W-remain =Pr W active -P W It is calculated by [method].

[0105] Then, the remaining capacity calculation means 76 calculates the remaining capacity P of the U phase as shown in the following equation. U-remain V-phase remaining capacity P V-remain, and the remaining capacity P of the W phase W-remain Of these, the smallest value is multiplied by 3 to obtain the remaining capacity P of the entire generator body 2. remain Calculate. P remain =MIN[(P U-remain ) or (P V-remain ) or (P W-remain )〕×3

[0106] In this way, the remaining capacity of the entire generator body 2 is the remaining capacity of each phase (P U-remain ,P V-remain ,P W-remain By multiplying the smallest value among them by 3, the remaining capacity P of the entire generator body 2 can be calculated based on the phase with the lowest remaining capacity, even when the remaining capacity of some phases is lower than that of others, such as when power is supplied to both three-phase and single-phase loads simultaneously. remain By calculating the remaining capacity P remain By connecting an additional three-phase load within the specified range, overcurrents can be prevented.

[0107] (3-6) Other (Means for calculating residual current value) Furthermore, the controller 70 detects the instantaneous voltage and instantaneous current values ​​and the remaining current value I that can be extracted from the generator body 2. remain A means 77 for calculating the remaining current value may also be provided.

[0108] This residual current value I remain As such, the aforementioned remaining current value calculation means 77 calculates the remaining current value I that can be extracted from the entire generator body 2. remain Calculate.

[0109] The following is the current value I U working ,I V working ,I W working This is the instantaneous value I of the current detected by the current detection means 62U, 62V, and 62W. U ,I V ,I W The effective value of the current calculated from this is I rms-U ,I rms-V ,I rms-W We define and explain it as being the same as [the other term]. Total remaining current value I of the generator unit 2 remain In performing the calculation, the remaining current value calculation means 77 uses the current value I of the U phase. U working V-phase current value I V working , and, the operating current value I of the W phase W working And the rated current value Ir of the U phase of the generator body 2, which has been previously stored in the memory means 75. U , V-phase rated current value Ir V And the rated current value Ir of the W phase W Using this, the residual current I of the U phase of the generator body 2 U-remain , residual current I of the V phase V-remain , and the residual current I of the W phase W-remain The following equations apply to each of these: I U-remain =Ir U -I U working I V-remain =Ir V -I V working I W-remain =Ir W -I W working It is calculated by [method].

[0110] The residual current value calculation means 77 calculates the residual current I of the U phase as shown in the following equation. U-remain , residual current I of the V phase V-remain , and the residual current I of the W phase W-remain Of these, the one with the smallest value is the total residual current value I of the generator body 2. remain It is calculated as follows. I remain =MIN[(I U-remain ) or (I V-remain ) or (I W-remain )〕

[0111] (4)Display means As shown in Figures 1 and 2, the remaining capacity display device 60 of the present invention displays the remaining capacity P of the entire generator body 2 calculated by the remaining capacity calculation means 76 of the controller 70 described above. remain A display means 80, such as a monitor screen, is provided to display the information.

[0112] In the illustrated example, the remaining capacity P of the entire generator body 2 is calculated by the remaining capacity calculation means 76. remain Along with this, the remaining current value I of the entire generator body 2 calculated by the aforementioned remaining current value calculation means 77 remain By also displaying the remaining capacity P when connecting a load, users can check the remaining capacity P remain Furthermore, the remaining current value I remain I have also made it possible to refer to that information.

[0113] The example shown in the illustration depicts a screen display when no load is connected to either the three-phase output terminal block 51 or the single-phase output terminal block 52. The display screen shows the rated active power Pr of the entire generator body 2. active The remaining capacity P of the load L1 that can be connected to the three-phase output terminal block 51 is 36kW, and the rated current value Ir of the entire generator body 2 is 118.0A. remain and remaining current value I remain It is displayed as follows.

[0114] [Effect, etc.] Table 1 below shows the differences in the displayed remaining capacity when the remaining capacity of the entire three-phase system of an AC generator 1, which is equipped with an engine with a rated output of 42.5 kW and a generator body 2 with a rated output of 45 kVA (at 60 Hz), is displayed using the remaining capacity display method of the present invention and the method described in the aforementioned Patent Document 2.

[0115] [Table 1]

[0116] As mentioned above, in the configuration of the comparative example (Patent Document 2), the difference between the generator rated output [kVA] [Table 1 (2)] and the apparent power used [kVA] [Table 1 (5)] is calculated as the remaining capacity [kVA] [Table 1 (7)], The difference between the engine's rated output [kW] [Table 1 (1)] and the active power used [kW] [Table 1 (6)] is calculated as the remaining power [kW]. The remaining capacity of the active power value [kW] is displayed as the smaller of the remaining capacity [kVA] [Table 1 (7)] and the remaining power [kW].

[0117] As a result, depending on the usage conditions, such as in the cases of "Condition 1" and "Condition 3" in Table 1, the sum of the displayed remaining capacity [kW] [Displayed value in (9) of Table 1] and the active power value of the power used [kW] [(6) of Table 1] may exceed the rated active power [kW] of the generator itself [(4) of Table 1]. Even when a new load is connected within the range of the displayed remaining capacity [kW], it is possible that a load exceeding the rated active power [kW] of the generator itself may be connected.

[0118] In this way, if a load exceeding the rated active power [kW] of the generator is connected, the generator may experience an overcurrent, and the AC generator may shut down due to the activation of safety devices to prevent burnout of the armature windings.

[0119] In contrast, the method of the present invention results in a remaining capacity P remain When displaying the active power used P [kW] and the calculated remaining capacity P remain The sum of [kW] and the rated active power Pr of the generator unit 2 is always equal to the rated active power Pr of the generator unit 2. active By matching the [kW] value, it is possible to connect new loads within the calculated remaining capacity range, thereby preventing excessive loads from being connected to the generator itself.

[0120] [Example of modification] (Addition of determination means) In the embodiments described above, as shown in Figures 1 and 2, the remaining capacity is displayed by showing the remaining capacity calculated by the remaining capacity calculation means 76 as a "numerical value." However, in addition to, or instead of, such a numerical display of the remaining capacity, a determination process is performed to determine whether or not it is possible to connect a load that is scheduled to be newly connected, and the result of this determination is displayed on the display means 81 as a display of the remaining capacity.

[0121] In this case, the determination means 78 enclosed by a dashed line in Figure 3 is added to the aforementioned controller 70.

[0122] The determination of whether a newly connected load can be connected is made by the remaining capacity P of the entire generator body 2 calculated by the remaining capacity calculation means 76. remain Then, compare the remaining capacity P with the active power consumption [kW], which is the power consumption at the active power value of the newly connected three-phase load. remain Alternatively, the determination of whether connection is possible may be made if the active power consumption [kW] of the newly connected three-phase load is small.

[0123] However, the remaining capacity P calculated by the remaining capacity calculation means 76 remain Since the power factor used in the calculation corresponds to the power factor of the load already connected to the generator body 2, when connecting a new three-phase load with the same power factor as the already connected load, the generator body 2 will not be overloaded by connecting the load within the range of the remaining capacity calculated by the remaining capacity calculation means 76.

[0124] However, when connecting a load with a lower power factor than an already connected load, even if the new three-phase load is connected within the displayed remaining capacity range, the connected load may exceed the rated current value Ir[A] of the generator unit 2.

[0125] Therefore, when determining whether or not a connection is possible when the load to be newly connected is a three-phase load, it is desirable to also consider the power factor of the three-phase load to be newly connected.

[0126] Therefore, in this embodiment, the determination means 78 provided in the controller 70 is configured to determine whether or not a load can be connected by considering not only the active power consumption [kW] of the three-phase load to be newly connected, but also its power factor.

[0127] To enable such determination, the storage means 75 of the controller 70 stores load information including the power factor of the three-phase load to be newly connected and the active power consumption [kW], which is the power consumption at the active power value.

[0128] This load information may be stored in the storage means 75 by the user entering the load information on the spot according to the instructions on the input screen displayed on the touch panel, or the load information of frequently connected equipment (e.g., submersible pumps) may be stored in the storage means 75 in advance, for example, at the time of factory shipment of the AC generator 1.

[0129] For example, when determining whether a connection is possible based on load information entered by the user, as shown on the right side of Figure 6, the active power consumption in kW and the power factor from the load information entered by the user can be displayed, and whether or not the connection of the load is possible can be indicated by the illumination of either the "NG" lamp or the "OK" lamp.

[0130] Furthermore, when determining whether a new load can be connected based on load information stored in a storage device beforehand, as shown on the left side of Figure 6, a lamp may be provided for each load corresponding to the pre-stored load information, and the determination result may be displayed by lighting up the lamp for a connectable load and turning off the lamp for an unconnectable load.

[0131] In order to have the determination means 78 perform the aforementioned determination process, the determination means 78 is instructed to use the current value I of the total three-phase current of the generator body 2 at the present time, which is calculated by the aforementioned active power usage calculation means 71, from the total active power usage P of the generator body 2. working A current usage value calculation unit 78a that determines the current usage value, The total current value I of the three phases is calculated from the rated current value Ir of the generator body 2. working Subtracting this, the total remaining current value for the three phases is I remain Calculate (I remain =Ir-I working The remaining current value calculation unit 78b performs the following: From the power factor and active power consumption of the load to be newly connected, stored in the memory means 75, the load current value I, which is the current value flowing through the load to be newly connected, is calculated. load A load current value calculation unit 78c that calculates the load current value, The aforementioned residual current value I remain and the aforementioned load current value Iload By comparing with the load current value I load if the load current value I remain is lower than the residual current value I remain (I load >I load ), a comparison and determination unit 78d for determining that the additional load can be connected is provided.

[0132] In addition, as shown in FIG. 2, in the configuration of this embodiment in which a residual current value calculation means 77 for calculating the residual current value I remain of the entire generator main body 2 is already provided in the controller 70, this residual current value calculation means 77 may also serve as the used current value calculation unit 78a and the residual current value calculation unit 78b provided in the determination means 78.

[0133] Further, the comparison of the magnitudes of the residual current value I remain and the load current value I load can be performed not only by directly comparing the residual current value I remain and the load current value I load , but also by comparing the sum of the used current value I working and the load current value I load of the generator main body 2 with the rated current value Ir of the generator main body 2. It is also possible to determine that the additional load can be connected when the sum of the used current value I working and the load current value I load is lower than the rated current value Ir (Ir>I working +I load ).

[0134] Hereinafter, as an example, a case where a three-phase load is newly connected to the three-phase output terminal block 51 of the AC generator 1 including the generator main body 2 with a rated output Pr of 45 kVA and a rated current Ir of 118 A at 60 Hz and three-phase 220 V will be described as an example.

[0135] Assuming that a load is already connected to the above AC generator 1 and the state is such that the active power P in use is 20 kW, the apparent power S in use is 25 kVA, and the power factor is 0.8 as shown in Table 2 below, the remaining capacity P remain of the entire AC generator 1 at this time is 16 kW.

[0136]

Table 2

[0137] When determining whether it is possible to newly connect a three-phase load with a power consumption of 7.5 kW and a power factor of 0.4 to the AC generator 1 in this state, the current consumption value calculation unit 78a of the determination means 78 calculates the total three-phase current consumption value I of the generator main body 2 at the time of detecting the instantaneous value of the voltage and the instantaneous value of the current working as the current consumption value I U working , I V working , I W working (that is, the effective value of the current I rms-U , I rms-V , I rms-W ) and obtains it as the maximum value of any one of them. I working = MAX〔(I U working ) or (I V working ) or (I W working )〕

[0138] The total residual current value I remain in the AC generator 1 is the value obtained by subtracting the current consumption value I working from the rated current value Ir of the generator main body 2, that is, I remain = Ir - I working Therefore, in the example of Table 2, the residual current value I remain is I remain = 118 [A] - 65.6 [A] = 52.4 [A] and becomes.

[0139] On the other hand, from the power factor and the consumed active power in the load information of the newly planned connection, the load current value I load flowing through the load to be newly connected is I load = the consumed power of the load [kW] / (V·√3·power factor), so I load = 7.5 [kW]·1000 / (220 [V]·√3·0.4) = 49.2 [A] and becomes.

[0140] Therefore, in the above example, the load current value I load The remaining current value I of the entire generator body 2 remain A value lower than [I remain (52.4[A])>I load (49.2[A])) and the current value used I working and load current value I load The sum of the values ​​is lower than the rated current value Ir [Ir(118[A])>Ir working (52.4[A])+I load (49.2[A])) As such, the comparison and determination unit 78d of the determination means 78 determines that it is possible to connect the load that is to be newly connected, and lights up the "OK" lamp of the display means.

[0141] This allows users to accurately determine whether or not it is possible to connect a newly scheduled load. [Explanation of symbols]

[0142] 1 AC generator 2. Generator body UU Aimaki Line VV phase winding WW phase winding V' Auxiliary winding N neutral point v, w, u, n, v' Output section (of the generator body) w2,u2 middle tap 10 Power output system 20U, 20V, 20W, 20V' Main output circuit 30U,30V,30W three-phase output circuit 31 Three-phase circuit breaker 40U, 40N, 40W, 40V' Single-phase output circuit 41 Single-phase circuit breaker 51 Three-phase output terminal block 52 Single-phase output terminal block 60 Remaining capacity display device 61U, 61V, 61W, 61N, 61V' Voltage detection means (voltage detector) 62U, 62V, 62W, 62V' Current detection means (current detector) 70 Control device (controller) 71 Calculation means for used active power 72 Calculation means for apparent power used 73 Power factor calculation means 74 Calculation means for rated active power 75 Memory means 76 Remaining capacity calculation means 77 Remaining current value calculation means 78 Judgment means 78a Used current value calculation section 78b Remaining current value calculation section 78c Load current value calculation section 78d Comparison / judgment section 80, 81 Display means (monitor) 100 AC generator 102 Generator main body 110 Power output system 120 Output circuit 130 (130U, 130V, 130W) Three-phase output circuit 140 (140U, 140V’, 140W) Single-phase output circuit 151 Three-phase output terminal block 152 Single-phase output terminal block L1~L4 Load V (V U , V V , V W ) Instantaneous value of voltage V rms (V rms-U , V rms-V , V rms-W , V rms-V’ ) Effective value of voltage I (I U , I V , I W , I v’ ) Instantaneous value of current I rms (I rms-U , I rms-V , I rms-W , I rms-V’ ) Effective value of current P, P U , P V , P W , P N Used active power S,S U ,S V ,S W ,S N Apparent power used PF, PF U ,PF V ,PF W Power factor Pr Generator Rated Output Pr active ,Pr U active ,Pr V active ,Pr W active Rated active power P remain Remaining capacity I working ,I U working ,I V working ,I W working Current usage value Ir, Ir U ,Ir V ,Ir W Rated current value of the generator itself I remain ,I U-remain ,I v-remain ,I w-remain Residual current value I load Load current value

Claims

1. In a method for displaying the remaining capacity of an AC generator, in which a power output system is formed by an output terminal block to which a load can be connected and an output circuit connecting the output terminal block and the output section of the generator body, A voltage detection process that sequentially detects the instantaneous value of the voltage of the generator body, A current detection process that sequentially detects the instantaneous value of the current in the generator body, Based on the instantaneous voltage and current values, a process for calculating the active power used, which is the power used by the generator body at the time the instantaneous voltage and current values ​​are detected, is performed. An apparent power usage calculation process that calculates the apparent power usage, which is the power used by the generator body at the time of detection, based on the effective value of the voltage calculated based on the instantaneous value of the voltage and the effective value of the current calculated based on the instantaneous value of the current, A power factor calculation process that calculates the ratio of the active power used and the apparent power used as the power factor of the generator body at the time of detection, A rated active power calculation process, which involves correcting the generator rated output, which is the rated output of the generator body, using the power factor, to calculate the rated active power of the generator body at the time of detection, and thereby calculating the rated active power as the rated active power of the generator body at the time of detection. A remaining capacity calculation process that calculates the difference between the rated active power and the active power used as the remaining capacity of the AC generator at the time of detection. A method for displaying remaining capacity in an AC generator, characterized by including the following:

2. The method for displaying remaining capacity in an AC generator according to claim 1, characterized in that the above-mentioned active power used is calculated by integrating the product of the instantaneous value of the voltage and the instantaneous value of the current and averaging it over one period.

3. The method for displaying remaining capacity in an AC generator according to claim 1, further comprising a remaining capacity display process for displaying the remaining capacity on a display means.

4. A determination process to determine whether or not it is possible to connect a load that is scheduled to be newly connected, A method for displaying remaining capacity in an AC generator according to any one of claims 1 to 3, characterized in that it includes a determination result display process for displaying the determination result performed in the determination process on a display means.

5. The aforementioned determination process further, A current usage value calculation process that determines the current usage value of the generator body at the time of detection from the above-mentioned active power usage, A remaining current value calculation process that calculates the remaining current value by subtracting the usage current value from the rated current value of the generator body, A load current value calculation process calculates the load current value, which is the current value that flows through the load when it is connected, based on the active power consumption, which is the power consumption of the load at its active power value, and the power factor of the load to be newly connected. The method for displaying remaining capacity in an AC generator according to claim 4, characterized in that it includes a comparison and determination process, which involves comparing the remaining current value with the load current value and determining that it is possible to connect the load to be newly connected if the load current value is smaller than the remaining current value.

6. A method for displaying remaining capacity in an AC generator according to any one of claims 1 to 3, characterized in that the detection of instantaneous voltage values ​​and instantaneous current values ​​in the voltage detection process and the current detection process is performed for each phase of the generator body.

7. In a display device for remaining capacity in an AC generator, the power output system is formed by an output terminal block to which a load can be connected and an output circuit connecting the output terminal block and the output section of the generator body, Voltage detection means for sequentially detecting the instantaneous value of the voltage of the generator body, A current detection means for sequentially detecting the instantaneous value of the current in the generator body, A means for calculating the active power used, which is the power used by the generator body at the time of detection of the instantaneous voltage and current values, based on the instantaneous voltage and current values, An apparent power calculation means for calculating the apparent power used, which is the power used by the generator body at the time of detection, based on the effective value of the voltage calculated based on the instantaneous value of the voltage and the effective value of the current calculated based on the instantaneous value of the current, A power factor calculation means that calculates the ratio of the active power used to the apparent power used as the power factor of the generator body at the time of detection, A rated active power calculation means calculates the rated active power of the generator body at the time of detection by correcting the generator rated output, which is the rated output of the generator body stored in the memory means, using the power factor, A remaining capacity calculation means calculates the difference between the rated active power and the active power used as the remaining capacity of the AC generator at the time of detection. A remaining capacity display device for an AC generator, characterized by including the following:

8. The remaining capacity display device for an AC generator according to claim 7, characterized in that the means for calculating the active power used calculates the active power used by integrating the product of the instantaneous value of the voltage and the instantaneous value of the current and averaging it over one period.

9. The remaining capacity display device for an AC generator according to claim 7, further comprising a display means for displaying the remaining capacity.

10. A remaining capacity display device for an AC generator according to any one of claims 7 to 9, characterized in that it includes a determination means for determining whether or not it is possible to connect a load that is to be newly connected, and for displaying the determination result on a display means.

11. The determination means, A current usage value calculation unit that calculates the current usage value of the generator body at the time of detection from the active power usage, A residual current value calculation unit that calculates a residual current value by subtracting the usage current value from the rated current value of the generator body stored in the storage means, A load current value calculation unit calculates a load current value, which is the current value that flows through the load when the load to be newly connected is connected, based on the active power consumption, which is the power consumption of the load to be newly connected, and the power factor, which are stored in the storage means, The remaining capacity display device for an AC generator according to claim 10, characterized in that it includes a comparison and determination unit that compares the remaining current value with the load current value and determines that it is possible to connect the load to be newly connected if the load current value is smaller than the remaining current value.

12. The remaining capacity display device for an AC generator according to any one of claims 7 to 9, characterized in that the voltage detection means and the current detection means detect the instantaneous value of the voltage and the instantaneous value of the current on a phase-by-phase basis of the generator body.

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