Diesel generating set and control method thereof

Abstract

The invention provides a diesel generating set and a control method thereof, a rated rotating speed correction unit determines a target rated rotating speed according to a load change estimated value and a standard rated rotating speed when a liability of the diesel generating set changes, and transmits the target rated rotating speed to a central control unit; the rotating speed sensor monitors the rotating speed of a flywheel in the diesel generating set and transmits the rotating speed of the flywheel to the central control unit; and the central control unit outputs corresponding excitation current to the oil injection control unit according to the target rated rotating speed and the flywheel rotating speed. The target rated rotating speed is adjusted in advance on the basis of the load change estimated value, and the rotating speed set change condition is ahead of the change of the actual load, so that the transient process of suddenly loading / unloading the load of the generator set can be matched when the rotating speed of the diesel engine is actually increased / reduced, and the advanced rotating speed control of suddenly loading / unloading the load of the generator set is realized; and the transient frequency adjustment rate and the stable time index of the generator set are improved.

Description

Technical Field

[0001] The present invention relates to the field of generators, and in particular to a diesel generator set and a control method thereof. Background Art

[0002] In current diesel generator sets, the speed control system of the diesel engine is responsible for speed control. However, the speed control system reacts slowly, resulting in poor transient frequency adjustment rate and frequency stabilization time of the generator set after the speed of the diesel generator is adjusted.

[0003] In this case, how to ensure the transient frequency index of the generator set has become a difficult problem that technical personnel in this field are concerned about. Summary of the invention

[0004] The object of the present invention is to provide a diesel generator set and a control method thereof to improve the above-mentioned problems.

[0005] In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:

[0006] In a first aspect, an embodiment of the present invention provides a diesel generator set, the diesel generator set comprising a rated speed correction unit, a speed sensor, a central control unit and an injection control unit, the central control unit being connected to the rated speed correction unit, the speed sensor and the injection control unit respectively;

[0007] The rated speed correction unit is used to determine the target rated speed according to the load change estimate and the standard rated speed when the liability of the diesel generator set changes, and transmit the target rated speed to the central control unit, wherein the load change estimate is the difference between the target load value and the historical load value before the change;

[0008] The speed sensor is used to monitor the flywheel speed in the diesel generator set and transmit the flywheel speed to the central control unit;

[0009] The central control unit is used to output a corresponding excitation current to the injection control unit according to the target rated speed and the flywheel speed.

[0010] In a second aspect, an embodiment of the present invention provides a diesel generator set control method, which is applied to the above-mentioned diesel generator set, and the method includes:

[0011] The rated speed correction unit determines the target rated speed according to the load change estimate and the standard rated speed when the load of the diesel generator set changes, and transmits the target rated speed to the central control unit, wherein the load change estimate is the difference between the target load value and the historical load value before the change;

[0012] The speed sensor monitors the speed of the flywheel in the diesel generator set and transmits the speed of the flywheel to the central control unit;

[0013] The central control unit outputs a corresponding excitation current to the fuel injection control unit according to the target rated speed and the flywheel speed.

[0014] Compared with the prior art, the embodiment of the present invention provides a diesel generator set and a control method thereof, wherein the diesel generator set includes a rated speed correction unit, a speed sensor, a central control unit and an injection control unit, wherein the central control unit is connected to the rated speed correction unit, the speed sensor and the injection control unit respectively; the rated speed correction unit is used to determine the target rated speed according to the load change estimate and the standard rated speed when the liability of the diesel generator set changes, and transmit the target rated speed to the central control unit, wherein the load change estimate is the difference between the target load value and the historical load value before the change; the speed sensor is used to monitor the flywheel speed in the diesel generator set, and transmit the flywheel speed to the central control unit; the central control unit is used to output the corresponding excitation current to the injection control unit according to the target rated speed and the flywheel speed. Since the target rated speed is adjusted in advance based on the load change estimate, the speed setting change is ahead of the actual load change, so that when the diesel engine actually increases / decreases the speed, it can match the transient process of the sudden increase / sudden unloading of the generator set, realize the advance speed control of the sudden increase / sudden unloading of the generator set, and improve the transient frequency adjustment rate and stabilization time index of the generator set.

[0015] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is one of the structural schematic diagrams of a diesel generator set provided in an embodiment of the present invention.

[0018] Figure 2 The second structural schematic diagram of the diesel generator set provided in an embodiment of the present invention.

[0019] Figure 3 A schematic flow chart of a diesel generator set control method provided in an embodiment of the present invention.

[0020] In the figure: 10-central control unit; 20-rated speed correction unit; 30-speed sensor; 40-injection control unit; 50-load control unit. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0024] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0025] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0026] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" 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 it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0028] In an optional implementation, the speed control for periodic sudden load addition and removal is completed by the speed control system of the diesel engine. The speed control system of the generator set is mainly composed of a speed sensor, an ECU, and an injection control unit. The ECU monitors the speed of the diesel engine in real time by connecting to the speed sensor installed on the flywheel housing of the diesel engine. The ECU compares the detected speed of the diesel engine with the rated speed set inside the ECU.

[0029] When the actual speed of the diesel engine is lower than the set speed, the ECU compares the difference between the actual speed and the set speed, and proportionally increases the current output to the injection control unit based on the difference. The diesel engine's fuel intake increases, the combustion volume increases, and the diesel engine speed increases.

[0030] When the speed is higher than the set speed, the ECU compares the difference between the current speed and the set speed, and proportionally reduces the current output to the injection control unit based on the difference. The diesel engine's fuel intake increases, the combustion volume decreases, and the diesel engine speed decreases.

[0031] This speed control system is an automatic closed-loop control system, and the speed control process of the diesel engine lags behind the change process of the actual speed of the diesel engine. The speed control system reacts slowly, resulting in poor transient frequency adjustment rate and frequency stabilization time of the generator set after the diesel engine speed is adjusted. In order to ensure the transient frequency index of the generator set, it is generally necessary to increase the power of the diesel engine, which leads to an increase in the weight and volume of the diesel generator set.

[0032] In order to solve the above problems, the present invention provides a method for automatically adjusting the speed of a diesel engine of a diesel generator set according to changes in the estimated load, so as to achieve advance speed control when the transient load of the diesel generator set changes, thereby achieving the goal of improving the transient frequency index of the generator set.

[0033] Specifically, please refer to Figure 1 , Figure 1 This is one of the structural schematic diagrams of a diesel generator set provided in an embodiment of the present invention. The diesel generator set includes a rated speed correction unit 20, a speed sensor 30, a central control unit 10 and an injection control unit 40, and the central control unit 10 is connected to the rated speed correction unit 20, the speed sensor 30 and the injection control unit 40 respectively.

[0034] The central control unit 10 may be an electronic controller (Electronic Control Unit, detection ECU) or other electronic speed regulators capable of setting rated speed in real time through communication.

[0035] The rated speed correction unit 20 is used to determine the target rated speed according to the load change estimate and the standard rated speed when the load of the diesel generator set changes, and transmit the target rated speed to the central control unit 10, wherein the load change estimate is the difference between the target load value and the historical load value before the change.

[0036] The speed sensor 30 is used to monitor the speed of the flywheel in the diesel generator set and transmit the speed of the flywheel to the central control unit 10 .

[0037] The central control unit 10 is used to output a corresponding excitation current to the injection control unit 40 according to the target rated speed and the flywheel speed.

[0038] Since the target rated speed is adjusted in advance based on the estimated load change, the speed setting change of the entire control unit is ahead of the actual load change. Through the internal execution time delay of this system, the diesel engine can actually increase / decrease the speed to match the transient process of the sudden increase / sudden unloading of the generator set, realize the advance speed control of the sudden increase / sudden unloading of the generator set, and improve the transient frequency adjustment rate and stabilization time index of the generator set.

[0039] Based on the foregoing, regarding how the central control unit 10 outputs a corresponding excitation current to the injection control unit 40 according to the target rated speed and the flywheel speed, the embodiment of the present invention also provides an optional implementation, please refer to the following.

[0040] When the flywheel speed is lower than the target rated speed, the central control unit 10 is used to increase the excitation current output to the injection control unit 40 .

[0041] When the flywheel speed is higher than the target rated speed, the central control unit 10 is used to reduce the excitation current output to the injection control unit 40 .

[0042] In an optional embodiment, the central control unit 10 is used to determine the current adjustment amplitude of the excitation current based on the current speed difference ratio and the current excitation current, wherein the current speed difference ratio is the ratio of the absolute value of the difference between the flywheel speed and the target rated speed to the target rated speed, and the current adjustment amplitude is the product of the current excitation current and the current speed difference ratio.

[0043] It should be noted that when the excitation current output to the injection control unit 40 is increased, the current adjustment amplitude is the excitation current increase amplitude, and when the excitation current output to the injection control unit 40 is reduced, the current adjustment amplitude is the excitation current decrease amplitude.

[0044] It should be understood that when the load is suddenly added, the actual flywheel speed of the diesel engine is lower than the newly set target rated speed. The central control unit 10 proportionally increases the current output to the fuel injection control unit according to the current speed difference ratio, the diesel engine fuel intake increases, the combustion volume increases, and the diesel engine speed increases. When the load is suddenly added, the speed changes from the rated speed, and the sudden load is added on the basis of a higher speed. Compared with the original sudden load from the standard rated speed, the frequency transient adjustment rate and stabilization time are improved.

[0045] It should be understood that when the load is suddenly reduced, the actual flywheel speed of the diesel engine is lower than the newly set target rated speed. The central control unit 10 proportionally reduces the current output to the fuel injection control unit according to the current speed difference ratio, the diesel engine fuel intake increases, the combustion volume decreases, and the diesel engine speed decreases. When the load is suddenly reduced, the speed changes from the rated speed, and the load is suddenly reduced on the basis of a lower speed. Compared with the original sudden load reduction from the standard rated speed, the frequency transient adjustment rate and stabilization time are improved.

[0046] In an optional implementation, the rated speed correction unit 20 is used to determine the rated speed adjustment range according to the load change estimate.

[0047] The rated speed correction unit 20 is used to increase the rated speed adjustment range on the basis of the standard rated speed in the event of a sudden load increase, so as to determine a target rated speed.

[0048] The rated speed correction unit 20 is used to reduce the rated speed adjustment range on the basis of the standard rated speed in the case of a sudden load reduction, so as to determine the target rated speed.

[0049] Optionally, the rated speed correction unit 20 is used to determine the rated speed adjustment range according to the load change estimate and a pre-configured conversion relationship, wherein the conversion relationship represents a conversion formula between the load change estimate and the rated speed adjustment range.

[0050] Please refer to Figure 2 , Figure 2The second structural schematic diagram of the diesel generator set provided by the embodiment of the present invention is as follows: The diesel generator set further includes a load control unit 50 , and the load control unit 50 is connected to the rated speed correction unit 20 .

[0051] The load control unit 50 is used to obtain the load change estimated value, and send the obtained load change estimated value to the rated speed correction unit 20 .

[0052] Please refer to Figure 2 The diesel generator set also includes a load control unit 50 , which is connected to the central control unit 10 .

[0053] The load control unit 50 is used to detect the current real-time load of the diesel generator set and transmit the current real-time load to the central control unit 10 .

[0054] The central control unit 10 is further configured to use the standard rated speed as a new target rated speed when the current real-time load reaches the target load value.

[0055] The embodiment of the present invention also provides a diesel generator set control method, which can be applied to the above diesel generator set, please refer to Figure 3 , Figure 3 The flowchart of the diesel generator set control method provided by the embodiment of the present invention is as follows: The diesel generator set control method includes: S101, S102 and S103, which are specifically described as follows.

[0056] S101, when the load of the diesel generator set changes, the rated speed correction unit determines a target rated speed according to the load change estimate and the standard rated speed, and transmits the target rated speed to the central control unit.

[0057] The load change estimate is the difference between the target load value and the historical load value before the change.

[0058] S102, the speed sensor monitors the flywheel speed in the diesel generator set and transmits the flywheel speed to the central control unit.

[0059] S103, the central control unit outputs a corresponding excitation current to the fuel injection control unit according to the target rated speed and the flywheel speed.

[0060] Optionally, S103, the step of the central control unit outputting a corresponding excitation current to the fuel injection control unit according to the target rated speed and the flywheel speed includes:

[0061] S103-2, when the flywheel speed is lower than the target rated speed, the central control unit increases the excitation current output to the injection control unit;

[0062] S103-3, when the flywheel speed is higher than the target rated speed, the central control unit reduces the excitation current output to the injection control unit.

[0063] Optionally, S103, the step of the central control unit outputting a corresponding excitation current to the fuel injection control unit according to the target rated speed and the flywheel speed, further includes:

[0064] S103-1, the central control unit determines the current adjustment amplitude of the excitation current according to the current speed difference ratio and the current excitation current, wherein the current speed difference ratio is the ratio of the absolute value of the difference between the flywheel speed and the target rated speed to the target rated speed, and the current adjustment amplitude is the product of the current excitation current and the current speed difference ratio.

[0065] It should be noted that the diesel generator set control method provided in this embodiment can perform the functions and uses shown in the above diesel generator set embodiment to achieve the corresponding technical effects. For the sake of brief description, for parts not mentioned in this embodiment, please refer to the corresponding contents in the above embodiment.

[0066] In summary, an embodiment of the present invention provides a diesel generator set and a control method thereof, wherein the diesel generator set includes a rated speed correction unit, a speed sensor, a central control unit and an injection control unit, wherein the central control unit is connected to the rated speed correction unit, the speed sensor and the injection control unit respectively; the rated speed correction unit is used to determine the target rated speed according to the load change estimate and the standard rated speed when the liability of the diesel generator set changes, and transmit the target rated speed to the central control unit, wherein the load change estimate is the difference between the target load value and the historical load value before the change; the speed sensor is used to monitor the flywheel speed in the diesel generator set, and transmit the flywheel speed to the central control unit; the central control unit is used to output the corresponding excitation current to the injection control unit according to the target rated speed and the flywheel speed. Since the target rated speed is adjusted in advance based on the load change estimate, the speed setting change is ahead of the actual load change, so that when the diesel engine actually increases / decreases the speed, it can match the transient process of the sudden increase / sudden unloading of the generator set, realize the advance speed control of the sudden increase / sudden unloading of the generator set, and improve the transient frequency adjustment rate and stabilization time index of the generator set.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0068] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A diesel generator set, characterized in that: The diesel generator set comprises a rated speed correction unit, a speed sensor, a central control unit and an injection control unit, wherein the central control unit is connected to the rated speed correction unit, the speed sensor and the injection control unit respectively; The rated speed correction unit is used to determine the target rated speed according to the load change estimate and the standard rated speed when the liability of the diesel generator set changes, and transmit the target rated speed to the central control unit, wherein the load change estimate is the difference between the target load value and the historical load value before the change; The speed sensor is used to monitor the flywheel speed in the diesel generator set and transmit the flywheel speed to the central control unit; The central control unit is used to output a corresponding excitation current to the injection control unit according to the target rated speed and the flywheel speed.

2. The diesel generator set according to claim 1, characterized in that: When the flywheel speed is lower than the target rated speed, the central control unit is used to increase the excitation current output to the injection control unit; When the flywheel speed is higher than the target rated speed, the central control unit is used to reduce the excitation current output to the injection control unit.

3. The diesel generator set according to claim 2, characterized in that: The central control unit is used to determine the current adjustment amplitude of the excitation current based on the current speed difference ratio and the current excitation current, wherein the current speed difference ratio is the ratio of the absolute value of the difference between the flywheel speed and the target rated speed to the target rated speed, and the current adjustment amplitude is the product of the current excitation current and the current speed difference ratio.

4. The diesel generator set according to claim 1, characterized in that: The rated speed correction unit is used to determine the rated speed adjustment range according to the load change estimate; The rated speed correction unit is used to increase the rated speed adjustment range on the basis of the standard rated speed in the event of a sudden load, so as to determine the target rated speed; The rated speed correction unit is used to reduce the rated speed adjustment range on the basis of the standard rated speed in case of a sudden load reduction, so as to determine the target rated speed.

5. The diesel generator set according to claim 4, characterized in that: The rated speed correction unit is used to determine the rated speed adjustment range according to the load change estimate and a pre-configured conversion relationship, wherein the conversion relationship represents a conversion formula between the load change estimate and the rated speed adjustment range.

6. The diesel generator set according to claim 1, characterized in that: The diesel generator set further comprises a load control unit, which is connected to the rated speed correction unit; The load control unit is used to obtain the load change estimated value, and send the obtained load change estimated value to the rated speed correction unit.

7. The diesel generator set according to claim 1, characterized in that: The diesel generator set further comprises a load control unit, which is connected to the central control unit; The load control unit is used to detect the current real-time load of the diesel generator set and transmit the current real-time load to the central control unit; The central control unit is further configured to use the standard rated speed as a new target rated speed when the current real-time load reaches the target load value.

8. A diesel generator control method, characterized in that: Applied to the diesel generator set according to any one of claims 1 to 7, the method comprises: The rated speed correction unit determines the target rated speed according to the load change estimate and the standard rated speed when the load of the diesel generator set changes, and transmits the target rated speed to the central control unit, wherein the load change estimate is the difference between the target load value and the historical load value before the change; The speed sensor monitors the speed of the flywheel in the diesel generator set and transmits the speed of the flywheel to the central control unit; The central control unit outputs a corresponding excitation current to the fuel injection control unit according to the target rated speed and the flywheel speed.

9. The diesel generator control method according to claim 8, characterized in that: The step of the central control unit outputting a corresponding excitation current to the fuel injection control unit according to the target rated speed and the flywheel speed comprises: When the flywheel speed is lower than the target rated speed, the central control unit increases the excitation current output to the injection control unit; When the flywheel speed is higher than the target rated speed, the central control unit reduces the excitation current output to the injection control unit.

10. The diesel generator control method according to claim 9, characterized in that: The step of the central control unit outputting a corresponding excitation current to the fuel injection control unit according to the target rated speed and the flywheel speed also includes: The central control unit determines the current adjustment amplitude of the excitation current based on the current speed difference ratio and the current excitation current, wherein the current speed difference ratio is the ratio of the absolute value of the difference between the flywheel speed and the target rated speed to the target rated speed, and the current adjustment amplitude is the product of the current excitation current and the current speed difference ratio.

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