Overload protection device of generator set and power frequency generator set

Abstract

The utility model discloses an overload protection device of a generator set and a power frequency generator set, and the overload protection device cancels a circuit breaker at the output end of a main winding of an excitation generator, and is additionally provided with an output current detection module and an excitation control module. A generator output load current signal at the output end of a main winding of an excitation generator is detected in real time through an output current detection module connected with an excitation control module, and a corresponding excitation control signal is output to an automatic voltage regulator through the excitation control module according to the detected generator output load current signal. And the automatic voltage regulator controls the on-off of an excitation winding of the excitation generator according to the excitation control signal, so that the on-off between the excitation generator and the power supply module is controlled, and the on-off control of load power supply is realized. According to the invention, the safety and reliability of overload protection of the power frequency generator set can be effectively improved, and the reactive power loss is reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of industrial frequency generator sets, and in particular relates to an overload protection device for a generator set and an industrial frequency generator set. Background Art

[0002] like Figure 1 As shown, in the overload protection device of the current power frequency generator set, the output control of the main winding of the excitation generator mainly adopts a hydraulic or thermal circuit breaker. The overload protection device of the current generator set has the following problems:

[0003] 1. The output protection device (circuit breaker) is connected to the output end of the main winding of the excitation generator and carries a large current. When the excitation generator is overloaded, sparks will appear at the moment the circuit breaker trips, causing erosion of the circuit breaker contacts, etc., which poses certain safety hazards;

[0004] 2. The greater the current flowing, the greater the heat generated by the circuit breaker itself, which increases the power loss of the excitation generator and causes the temperature of the whole machine to rise, especially for thermal circuit breakers. The temperature has a greater impact on the overload trip coefficient. The higher the temperature, the lower the trip coefficient, and the easier it is to trip the protection in advance (premature protection before the rated power is reached), thus affecting the normal operation of the generator set;

[0005] 3. The wiring terminals of the circuit breaker are prone to loosening and poor contact due to heat.

[0006] Therefore, how to improve the safety and reliability of overload protection of power frequency generator sets and reduce reactive power loss is a problem that needs to be solved urgently in this field. Utility Model Content

[0007] In view of the defects in the prior art, the purpose of this application is to provide an overload protection device for a generator set and an industrial frequency generator set, which can effectively improve the safety and reliability of the overload protection of the industrial frequency generator set and reduce reactive power loss.

[0008] In order to achieve the above objectives, this application provides the following solutions:

[0009] According to a first aspect of the present application, the present application provides an overload protection device for a generator set, the generator set comprising an engine and an excitation generator, the engine being drivingly connected to the excitation generator, the overload protection device comprising an automatic voltage regulator, an output current detection module, an excitation control module and a power supply module, wherein:

[0010] The output end of the main winding of the excitation generator is connected to the input end of the power supply module, the power supply module is used to connect the load to supply power to the load, and the sampling winding, auxiliary winding and excitation winding of the excitation generator are respectively connected to the automatic voltage regulator;

[0011] The output current detection module is arranged on a connection line between the output end of the main winding of the excitation generator and the input end of the power supply module, the detection signal output end of the output current detection module is connected to the current detection signal input end of the excitation control module, and the output current detection module is used to detect the generator output load current signal at the output end of the main winding of the excitation generator, and send the generator output load current signal to the excitation control module;

[0012] The excitation control module is used to output a corresponding excitation control signal to the automatic voltage regulator according to the load current signal output by the generator;

[0013] The control signal input end of the automatic voltage regulator is connected to the control signal output end of the excitation control module. The automatic voltage regulator is used to control the on-off of the excitation winding of the excitation generator according to the excitation control signal to control the on-off between the excitation generator and the power supply module.

[0014] Preferably, the overload protection device further comprises a power supply switch, the signal output end of the power supply switch is connected to the power supply signal input end of the excitation control module, wherein:

[0015] The power supply switching switch is used to accept user operation to switch the power supply state of the excitation generator to the load according to the user operation.

[0016] Preferably, the power supply switching switch is a push button switch.

[0017] Preferably, the overload protection device further comprises a power supply status indicator light, the signal input end of the power supply status indicator light is connected to the power supply status signal output end of the excitation control module, wherein:

[0018] The power supply status indicator light is used to indicate the power supply status of the excitation generator to the load.

[0019] Preferably, the power supply status indicator light is also used to indicate whether the load current signal output by the generator exceeds the rated output current of the generator.

[0020] Preferably, the excitation control module is also connected to the start control circuit and the flameout control circuit of the engine, and the overload protection device further includes a start-stop switch, which is connected to the start-stop signal input terminal of the excitation control module, wherein:

[0021] The start-stop switch is used to control the start and stop of the engine.

[0022] Preferably, the overload protection device also includes a power supply module for supplying power to the excitation control module, the power supply module includes a battery, a power conversion module and a charging coil arranged on the engine, the battery is connected to the power input terminal of the excitation control module, the output terminal of the charging coil is connected to the input terminal of the power conversion module, and the output terminal of the power conversion module is respectively connected to the power input terminal of the excitation control module and the battery.

[0023] Preferably, the output current detection module is a current transformer.

[0024] Preferably, the power supply module is a socket.

[0025] According to a second aspect of the present application, the present application provides an industrial frequency generator set, comprising an overload protection device for the generator set as described in any one of the first aspects above.

[0026] Due to the adoption of the above technical solution, this application has the following beneficial effects:

[0027] On the basis of the prior art, the present application eliminates the circuit breaker at the output end of the main winding of the excitation generator, and adds an output current detection module and an excitation control module. The output current detection module connected to the excitation control module is used to detect the generator output load current signal at the output end of the main winding of the excitation generator in real time, and the excitation control module outputs a corresponding excitation control signal to the automatic voltage regulator according to the detected generator output load current signal. The automatic voltage regulator controls the on-off of the excitation winding of the excitation generator according to the excitation control signal, thereby controlling the on-off between the excitation generator and the power supply module, and realizing the on-off control of the load power supply, so that the overload protection control of the industrial frequency generator set is safer and more reliable. In addition, since the circuit breaker of the heat-prone device is eliminated, the heat generated by the whole machine is smaller and the reactive loss is lower. At the same time, the problem of early protection caused by the influence of temperature on the thermistor circuit breaker is avoided, and the timing of overload protection execution is more accurate.

[0028] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation of the present application or the technical solution in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation or the prior art description. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings without paying creative work.

[0030] Figure 1 It is a structural schematic diagram of an overload protection device for a generator set in the prior art;

[0031] Figure 2 It is a schematic diagram of the structure of an overload protection device for a generator set in one embodiment of the present application. DETAILED DESCRIPTION

[0032] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0033] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined.

[0034] In this application, the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] In addition, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] like Figure 2 As shown, an embodiment of the present application provides an overload protection device for a generator set, the generator set includes an engine 100 and an excitation generator 200, the engine 100 is drivingly connected to the excitation generator 200, the overload protection device includes an automatic voltage regulator 1, an output current detection module 2, an excitation control module 3 and a power supply module 4, wherein:

[0037] The output end of the main winding of the excitation generator 200 is connected to the input end of the power supply module 4, and the power supply module 4 is used to connect the load to supply power to the load. The sampling winding, the auxiliary winding and the excitation winding of the excitation generator 200 are respectively connected to the automatic voltage regulator 1;

[0038] The output current detection module 2 is arranged on the connection line between the output end of the main winding of the excitation generator 200 and the input end of the power supply module 4. The detection signal output end of the output current detection module 2 is connected to the current detection signal input end of the excitation control module 3. The output current detection module 2 is used to detect the generator output load current signal at the output end of the main winding of the excitation generator 200, and send the generator output load current signal to the excitation control module 3;

[0039] The excitation control module 3 is used to output a corresponding excitation control signal to the automatic voltage regulator 1 according to the load current signal output by the generator;

[0040] The control signal input end of the automatic voltage regulator 1 is connected to the control signal output end of the excitation control module 3. The automatic voltage regulator 1 is used to control the on-off of the excitation winding of the excitation generator 200 according to the excitation control signal to control the on-off between the excitation generator 200 and the power supply module 4.

[0041] The working principle of the overload protection device of the generator set in this embodiment is as follows:

[0042] During the operation of the generator set, the output current detection module 2 detects the generator output load current signal at the output end of the main winding of the excitation generator 200 in real time, and sends the detected generator output load current signal to the excitation control module 3. The excitation control module 3 compares the detected generator output load current signal with the generator rated output current pre-stored in the excitation control module 3. When the detected generator output load current signal is greater than the generator rated output current, it indicates that the generator output load current of the generator set is overloaded. At this time, the excitation control module 3 outputs an excitation disconnection signal. The automatic voltage regulator 1 receives a signal (such as a high-level signal), and the automatic voltage regulator 1 does not supply power to the excitation winding of the excitation generator 200 (i.e., controls the excitation winding to be disconnected from the automatic voltage regulator 1) when triggered by the excitation disconnection signal. At this time, no current flows through the rotor of the excitation generator 200, so the rotor cannot establish a magnetic field, and the main winding of the excitation generator 200 cannot cut the magnetic flux lines to generate an output voltage, thereby achieving the purpose of cutting off the current output path between the excitation generator 200 and the power supply module 4, that is, cutting off the power supply of the generator set to the load, thereby realizing overload protection of the generator set.

[0043] It should be noted that the process in which the excitation control module 3 outputs the corresponding excitation control signal according to the generator output load current signal does not involve the improvement of the existing control program, and can be specifically implemented by the threshold memory and comparator provided by the excitation control module 3. For example, the detected generator output load current signal is compared with the rated output current of the generator pre-stored in the threshold memory by the comparator. When the detected generator output load current signal is greater than the rated output current of the generator, the automatic voltage regulator 1 is output with a high level to disconnect the excitation switch 11 inside it, so that the automatic voltage regulator 1 does not supply power to the excitation winding of the excitation generator 200. When the detected generator output load current signal is less than or equal to the rated output current of the generator, the comparator outputs a low level, so that the excitation switch 11 inside the automatic voltage regulator 1 continues to remain in the on state, and the main winding of the excitation generator 200 group continues to output current.

[0044] Specifically, in this embodiment, the excitation control module may adopt an MCU controller (ie, a single-chip microcomputer), and specifically may adopt an STM32 series single-chip microcomputer, such as a single-chip microcomputer of model STM32F103.

[0045] In this embodiment, the circuit breaker at the output end of the main winding of the excitation generator 200 is eliminated, and an output current detection module 2 and an excitation control module 3 are added. The output current detection module 2 connected to the excitation control module 3 is used to detect the generator output load current signal at the output end of the main winding of the excitation generator 200 in real time, and the excitation control module 3 outputs the corresponding excitation control signal to the automatic voltage regulator 1 according to the detected generator output load current signal. The automatic voltage regulator 1 controls the on-off of the excitation winding of the excitation generator 200 according to the excitation control signal, thereby controlling the on-off between the excitation generator 200 and the power supply module 4, and realizing the on-off control of the load power supply, so that the overload protection control of the industrial frequency generator set is safer and more reliable. In addition, since the circuit breaker of the heat-prone device is eliminated, the heat generation of the whole machine is smaller, and the reactive power loss is lower. At the same time, the problem of early protection caused by the influence of temperature on the thermistor circuit breaker is avoided, and the timing of the overload protection work is more accurate.

[0046] Specifically, in this embodiment, the output current detection module 2 adopts a current transformer, and the power supply module 4 adopts a socket.

[0047] In one embodiment, the overload protection device further includes a power supply switch 5, the signal output end of the power supply switch 5 is connected to the power supply signal input end of the excitation control module 3, and the power supply switch 5 is used to accept user operations to switch the on-off state between the excitation generator 200 and the power supply module 4 according to the user operations. Specifically, in this embodiment, the power supply switch 5 can be a button switch.

[0048] When the overload protection device shuts off the power supply of the generator set to the load because the load current signal output by the generator is too large, the user manually presses the power supply switching switch 5 again, and the power supply voltage switching switch gives a pulse signal to the excitation control module 3, and the excitation control module 3 outputs a low level to trigger the automatic voltage regulator 1 to close its internal excitation switch 11, so that the automatic voltage regulator 1 resumes the power supply to the excitation winding of the excitation generator 200, thereby resuming the power supply of the generator set to the load.

[0049] Regardless of whether the load current signal output by the generator is too large, the user can also switch the power supply state of the generator set to the load by pressing the power supply switch 5 as needed.

[0050] In one embodiment, the overload protection device also includes a power supply status indicator light 6, the signal input end of the power supply status indicator light 6 is connected to the power supply status signal output end of the excitation control module 3, and the power supply status indicator light 6 is used to indicate the power supply status of the excitation generator 200 to the load; the power supply status indicator light 6 is also used to indicate whether the generator output load current signal exceeds the rated output current of the generator.

[0051] The power supply status indicator 6 can well remind the user of the current power supply status of the generator set. For example, when the excitation generator 200 supplies power to the load and the load current signal output by the generator does not exceed the rated output current of the generator, the power supply status indicator 6 lights up green, when the excitation generator 200 does not supply power to the load, the power supply status indicator 6 does not light up, and when the excitation generator 200 supplies power to the load and the load current signal output by the generator exceeds the rated output current of the generator, the power supply status indicator 6 lights up red.

[0052] In one embodiment, the excitation control module 3 is also connected to the start control circuit 101 and the shutdown control circuit 102 of the engine 100, and the overload protection device also includes a start-stop switch 7, which is connected to the start-stop signal input end of the excitation control module 3, and the start-stop switch 7 is used to control the start and stop of the engine 100.

[0053] By setting the start-stop switch 7, the user can more conveniently manually control the start and stop of the engine 100. Specifically, when the start-stop switch 7 is placed in the start position, the excitation control module 3 transmits the engine 100 start control signal to the start control circuit 101, thereby controlling the engine 100 to start through the start control circuit 101; when the start-stop switch 7 is placed in the stop position, the excitation control module 3 transmits the engine 100 stop control signal to the flameout control circuit 102, thereby controlling the engine 100 to shut down through the flameout control circuit 102.

[0054] Specifically, in order to facilitate the operation and maintenance of the generator set, in one embodiment, the overload protection device of the present application may also include a control panel 8, so that the output current detection module 2, the excitation control module 3, the power supply module 4, the power supply switching switch 5, the power supply status indicator light 6 and the start-stop switch 7 can all be installed on the control panel 8.

[0055] In one embodiment, the overload protection device also includes a power module 9 for supplying power to the excitation control module 3, the power module 9 includes a battery 91, a power conversion module 92 and a charging coil 93 arranged on the engine 100, the battery 91 is connected to the power input terminal of the excitation control module 3, the output terminal of the charging coil 93 is connected to the input terminal of the power conversion module 92, and the output terminal of the power conversion module 92 is connected to the power input terminal of the excitation control module 3 and the battery 91 respectively.

[0056] During the operation of the engine 100, the flywheel equipped with a magnet on the engine 100 rotates and cuts the magnetic flux lines, thereby generating an induced voltage at the charging coil 93 (stator coil). The output end of the charging coil 93 outputs alternating current. The power conversion module 92 rectifies, filters and stabilizes the alternating current output by the charging coil 93, and outputs stable direct current to charge the battery 91 and / or power the excitation control module 3. When the battery 91 is removed or breaks down during the operation of the engine 100, the control module can also be powered by the power conversion module 92 to maintain the normal operation of the excitation control module 3.

[0057] It should be noted that the charging coil 93 is installed on the engine 100, and the magnet is installed on the flywheel, so that the charging coil 93 generates an induced voltage based on electromagnetic induction during the operation of the engine 100. The engine 100 structure and its power supply principle belong to the prior art and will not be described in detail here.

[0058] The embodiment of the present application also provides an industrial frequency generator set, including the overload protection device of the generator set in any of the above embodiments. The working principle of the industrial frequency generator set is the same as that of the overload protection device of the above generator set, and has the same effective effect as that of the overload protection device of the above generator set, which will not be repeated here.

[0059] Those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this specification.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application.

Claims

1. An overload protection device for a generator set, the generator set comprising an engine and an excitation generator, the engine being drivingly connected to the excitation generator, characterized in that: The overload protection device includes an automatic voltage regulator, an output current detection module, an excitation control module and a power supply module, wherein: The output end of the main winding of the excitation generator is connected to the input end of the power supply module, the power supply module is used to connect the load to supply power to the load, and the sampling winding, auxiliary winding and excitation winding of the excitation generator are respectively connected to the automatic voltage regulator; The output current detection module is arranged on a connection line between the output end of the main winding of the excitation generator and the input end of the power supply module, the detection signal output end of the output current detection module is connected to the current detection signal input end of the excitation control module, and the output current detection module is used to detect the generator output load current signal at the output end of the main winding of the excitation generator, and send the generator output load current signal to the excitation control module; The excitation control module is used to output a corresponding excitation control signal to the automatic voltage regulator according to the load current signal output by the generator; The control signal input end of the automatic voltage regulator is connected to the control signal output end of the excitation control module. The automatic voltage regulator is used to control the on-off of the excitation winding of the excitation generator according to the excitation control signal to control the on-off between the excitation generator and the power supply module.

2. The overload protection device for a generator set according to claim 1, characterized in that: It also includes a power supply switch, the signal output end of the power supply switch is connected to the power supply signal input end of the excitation control module, wherein: The power supply switching switch is used to accept user operation to switch the power supply state of the excitation generator to the load according to the user operation.

3. The overload protection device for a generator set according to claim 2, characterized in that: The power supply switching switch is a push button switch.

4. The overload protection device for a generator set according to claim 1, characterized in that: It also includes a power supply status indicator light, the signal input end of the power supply status indicator light is connected to the power supply status signal output end of the excitation control module, wherein: The power supply status indicator light is used to indicate the power supply status of the excitation generator to the load.

5. The overload protection device for a generator set according to claim 4, characterized in that: The power supply status indicator light is also used to indicate whether the generator output load current signal exceeds the rated output current of the generator.

6. The overload protection device for a generator set according to claim 1, characterized in that: The excitation control module is also connected to the start control circuit and the flameout control circuit of the engine. The overload protection device also includes a start-stop switch, which is connected to the start-stop signal input terminal of the excitation control module. The start-stop switch is used to control the start and stop of the engine.

7. The overload protection device of a generator set according to any one of claims 1 to 6, characterized in that: It also includes a power supply module for supplying power to the excitation control module, the power supply module includes a battery, a power conversion module and a charging coil arranged on the engine, the battery is connected to the power input terminal of the excitation control module, the output terminal of the charging coil is connected to the input terminal of the power conversion module, and the output terminal of the power conversion module is connected to the power input terminal of the excitation control module and the battery respectively.

8. The overload protection device for a generator set according to any one of claims 1 to 6, characterized in that: The output current detection module is a current transformer.

9. The overload protection device for a generator set according to any one of claims 1 to 6, characterized in that: The power supply module is a socket.

10. An industrial frequency generator set, characterized in that: An overload protection device for a generator set comprising any one of claims 1 to 9.

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