Excitation system for generator

Abstract

An excitation system for regulating excitation current in a generator is described. The excitation system includes a direct current (DC) to direct current (DC) converter configured to receive a first DC voltage input and convert the first DC voltage input to a second DC voltage output. The excitation system further includes an automatic voltage regulator (AVR) coupled to the DC to DC converter. The AVR is configured to receive the second DC voltage output from the DC to DC converter and control the second DC voltage output provided to the generator for regulating the excitation current in the generator. The second DC voltage output is controlled based on an output voltage of the generator to maintain the output voltage at a predetermined output voltage.

Description

[0001] Description

[0002] EXCITATION SYSTEM FOR GENERATOR

[0003] Technical Field

[0004] The present disclosure relates to an excitation system for generators. More particularly, the present disclosure relates to an excitation system capable of utilizing direct current (DC) voltage input from a generator set starting system to regulate excitation current in a generator.

[0005] Background

[0006] Generators are widely used in various applications, including construction, manufacturing, and power generation, for converting mechanical energy into electrical energy. Generators generally utilize an excitation system to generate and regulate the magnetic field necessary for power generation. Generally, an excitation system generates and controls an excitation current that establishes a magnetic field within the generator, facilitating the generation of electrical power. A Permanent Magnet Generator (PMG) or an additional auxiliary winding embedded in a stator of the generator may be employed to provide the excitation current.

[0007] United States Patent Application No. 20150364950A1 relates to an auxiliary excitation device applied to a generator with a self-excited automatic voltage regulator (AVR). The auxiliary excitation device is installed between a battery and the AVR and constantly monitors the status of output voltage of the generator. When the output voltage of the generator instantaneously drops to a preset variation level, the auxiliary excitation device will convert a DC voltage from the battery into an AC voltage and boost the AC voltage to an auxiliary AC power. The auxiliary power is outputted to the AVR for the AVR to output excitation power to the generator, thereby providing additional excitation power to the generator and raising the output power of the generator. Summary

[0008] In an aspect, the present disclosure relates to an excitation system for regulating excitation current in a generator. The excitation system includes a direct current (DC) to direct current (DC) converter configured to receive a first DC voltage input and convert the first DC voltage input to a second DC voltage output. The excitation system further includes an automatic voltage regulator (AVR) coupled to the DC to DC converter. The AVR is configured to receive the second DC voltage output from the DC to DC converter and control the second DC voltage output provided to the generator for regulating the excitation current in the generator. The second DC voltage output is controlled based on an output voltage of the generator to maintain the output voltage at a predetermined output voltage.

[0009] In another aspect, the present disclosure relates to a method for regulating excitation current in a generator. The method includes receiving, by a direct current (DC) to direct current (DC) converter, a first DC voltage input and converting, by the DC to DC converter, the first DC voltage input to a second DC voltage output. The method further includes receiving, by an automatic voltage regulator (AVR), the second DC voltage output from the DC to DC converter and controlling, by the AVR, the second DC voltage output provided to the generator for regulating the excitation current in the generator. The second DC voltage output is controlled based on an output voltage of the generator to maintain the output voltage at a predetermined output voltage.

[0010] In yet another aspect, the present disclosure relates to a generator system. The generator system includes a direct current (DC) power battery source configured to provide a first DC voltage input. The generator system further includes a generator configured to provide an output voltage and an excitation system for regulating excitation current in the generator. The excitation system includes a direct current (DC) to direct current (DC) converter configured to receive the first DC voltage input and convert the first DC voltage input to a second DC voltage output. The excitation system further includes an automatic voltage regulator (AVR) coupled to the DC to DC converter. The AVR is configured to receive the second DC voltage output from the DC to DC converter and control the second DC voltage output provided to the generator for regulating the excitation current in the generator. The second DC voltage output is controlled based on an output voltage of the generator to maintain the output voltage at a predetermined output voltage.

[0011] Brief Description of the Drawings

[0012] FIG. 1 is a view of an exemplary generator system, according to an embodiment of the present disclosure; and

[0013] FIG. 2 is a method for regulating excitation current in a generator of the generator system, in accordance with an embodiment of the present disclosure.

[0014] Detailed Description

[0015] Reference will now be made in detail to specific embodiments or features, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts.

[0016] Referring to FIG. 1, an exemplary generator system 100 is shown. The generator system 100 is configured to provide a power supply, including an output voltage, to an external load 102. The external load 102 may include any type of power-consuming system or device that receives and / or utilizes a power supply to perform one or more tasks, including, but not limited to, consumer devices, industrial drive motors, construction equipment, and the like. The generator system 100 may be employed in diverse environments, including but not limited to, power generation, industrial settings, construction sector, and the like. In most environments, the generator system 100 is utilized to provide power supply when a grid power supply is unavailable or as a backup during power outages. For example, the generator system 100 may be employed to power tools, machines, and equipment at a worksite where the availability of the grid power supply is limited or as a backup during unexpected power disruptions.

[0017] As shown in FIG. 2, the generator system 100 may include a generator set starting system 104, a generator set (also referred to as a genset) 106, and an excitation system 110. The generator set starting system 104 is configured to initiate a startup process of the generator set 106. To this end, the generator set starting system 104 includes, amongst other components (not shown), a DC power battery source 114 to provide electrical power to start an engine 116 of the generator set 106. The DC power battery source 114 includes one or more batteries that provide a steady supply of DC voltage.

[0018] The battery may be rechargeable battery that can be recharged using external power sources, such as, an AC power source. For example, the rechargeable battery may include, but not limited to, Lead-Acid battery, Lithium- Ion battery, Nickel-Cadmium battery, and the like. In some other embodiments, the battery may include a non-rechargeable battery that is designed for single use. For example, the non-rechargeable battery may include, but not limited to, an Alkaline battery, a Silver Oxide battery, and the like. The DC power battery source 114 may be a 12 Volts or 24 Volts power battery source depending upon the electrical power requirement of the engine 116 of the generator system 100.

[0019] The generator set 106 of the generator system 100 receives the DC voltage from the DC power battery source 114 and generates the output voltage for providing to the external load 102. The generator set 106 may include, amongst other components, the engine 116 and a generator 118. The engine 116 utilizes the DC voltage from the DC power battery source 114 to power various electrical components / sy stems, such as, an ignition system, a fuel injection system, and the like, within the engine 116. The engine 116 is configured to generate mechanical power (e.g., rotational motion) by utilizing one or more processes, such as combustion of a mixture of substances or application of alternative mechanisms. The engine 116 may include, but not limited to, a diesel engine, a heavy fuel engine, a gasoline engine, a gaseous fuel-powered engine, or any other engine known in the art now known or in the future developed. It will be appreciated that the detailed functioning of the engine 116 related to the production of mechanical power is well-known in the art and is not described here for the sake of brevity.

[0020] The generator 118 is configured to convert at least a portion of the mechanical power produced by the engine 116 to electrical power for supplying the output voltage to the external load 102. To this end, the generator 118 may be coupled to the engine 116 using known mechanical coupling means for receiving the mechanical power (for example, the rotational motions). The mechanical power from the engine 116 is utilized to rotate a rotor of the generator 118. As the rotor rotates, the magnetic field induces electrical currents in stator windings of the generator 118, thereby generating an AC electrical power supply (i.e., the output voltage).

[0021] The generator 118 may be a single-phase, two-phase, or a three- phase generator, depending upon the requirement of the generator system 100. In an example shown in FIG. 1, the generator 118 is a three-phase generator that provides a three-phase AC output voltage on the U, V, and W windings of the stator windings. It will be appreciated that the detailed functioning of the generator 118 related to the generation of the electrical power from the mechanical power is well-known in the art and is not described here for the sake of brevity.

[0022] The generator system 100 further includes an excitation system 110 for regulating excitation current in the generator 118. The excitation current corresponds to an electrical current that flows through rotor windings of the generator 118 to create the magnetic field in the rotor. In accordance with various embodiments, the excitation current is supplied to the generator 118 through the excitation system 110. The excitation system 110 adjusts the excitation current based on the output voltage of the generator 118 and a predetermined output voltage.

[0023] In accordance with various embodiments, the excitation system 110 includes a DC to DC converter 120 and an Automatic Voltage Regulator (AVR) 122 coupled to the DC to DC converter 120. In some embodiments, the DC to DC converter 120 (and / or its functionality) may be integrated into the AVR 122, although it is possible for the DC to DC converter 120 to remain external to the AVR 122, as shown in FIG. 1. The DC to DC converter 120 is configured to receive the DC voltage (interchangeably referred to as a first DC voltage input) from the DC power battery source 114 included in the generator set starting system 104 and convert the first DC voltage input to a second DC voltage output. The first DC voltage input may be a constant voltage independent of the output voltage of the generator 118. In accordance with various embodiments, the second DC voltage output may be different from the first DC voltage input. The second DC voltage output may correspond to a step up voltage level or a step down voltage level of the first DC voltage input depending upon an excitation requirement of the generator 118. In accordance with various embodiments, the excitation requirement corresponds to the amount of excitation current needed to establish and maintain the magnetic field in the rotor of the generator 118. The excitation requirement depends upon, amongst other factors, the predetermined output voltage (i.e., a desired output voltage) of the generator 118. Although the excitation system 110 is described to include the DC to DC converter 120 to receive the first DC voltage input and convert the first DC voltage input to the second DC voltage output, a person skilled in the art would appreciate that any other electrical device configured to perform the above functions can also be utilized instead of the DC to DC converter 120 in the excitation system 100.

[0024] The AVR 122 is configured to receive the second DC voltage output from the DC to DC converter 120 and control the second DC voltage output to generate a third DC voltage output. The third DC voltage output is provided to the generator 118 for regulating the excitation current in the generator 118. The second DC voltage output is controlled based on the output voltage of the generator 118 to maintain / regulate the output voltage of the generator 118 at the predetermined output voltage. The predetermined output voltage may be the desired or target output voltage defined by a user or operator based on a specific requirement of the application of the generator 118. In some embodiments, the predetermined output voltage may be a range having upper and lower limits for the output voltage of the generator 118. To this end, the AVR 122 may be equipped with one or more sensors, such as, a voltage sensor, to monitor the output voltage, for example, on the U, V, and W windings, of the generator 118. For example, the AVR 122 is configured to monitor (e.g., continuously monitor) the output voltage of the generator 118 and compare the output voltage of the generator 118 with the predetermined output voltage to determine a difference between the output voltage and the predetermined output voltage (e.g., how far the output voltage is from the predetermined output voltage). The AVR 122 may then control the second DC voltage output to generate the third DC voltage output based on the comparison. The third DC voltage output is then provided to the generator 118 to adjust or regulate the excitation current supplied to the rotor windings of the generator 118. By adjusting or regulating the excitation current, the magnetic field in the rotor of the generator 118 is controlled, thereby stabilizing and regulating the output voltage of the generator 118.

[0025] The AVR 122 is configured to monitor (e.g., continuously monitor) the output voltage of the generator 118 to maintain a stable and steady output voltage of the generator 118. For example, when the third DC voltage output is provided to the generator 118, the output voltage generated by the generator 118 may be again measured by the AVR 122 and based on the comparison of the output voltage with the predetermined output voltage, the third DC voltage output is provided to the generator 118 for regulation of the output voltage. The AVR 122 may repeat the process of adjusting the excitation current in the generator 118 accordingly to regulate the output voltage of the generator 118 in a closed loop manner.

[0026] Industrial Applicability

[0027] FIG. 2 illustrates a method 200 for regulating the excitation current in the generator 118 by way of a flowchart. The method 200 begins with the DC to DC converter 120 receiving the first DC voltage input at 202 and converting the first DC voltage input to the second DC voltage output at 204. At 206, the AVR 122 receives the second DC voltage output from the DC to DC converter 120. At 208, the AVR 122 controls the second DC voltage output provided to the generator 118 for regulating the excitation current in the generator 118. The AVR 122 controls the second DC voltage output based on the output voltage of the generator 118 to maintain the output voltage at the predetermined output voltage.

[0028] The present disclosure provides a method and system for regulating excitation current in the generator 118. The utilization of the DC power battery source 114 included in the generator set starting system 104 for providing the second DC voltage to the AVR 122 eliminates a need to have any additional component, such as a Permanent Magnet Generator (PMG) or an auxiliary winding embedded in a stator of the generator 118. The elimination of the additional components reduces the cost as well as the size and bulk of the generator system 100. Moreover, the elimination of the rotating component, such as the PMG, also reduces the parasitic load on a prime mover (such as, the engine 116) of the generator system 100.

[0029] It will be apparent to those skilled in the art that various modifications and variations can be made to the method and / or system of the present disclosure without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the method and / or system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalent.

Claims

Claims1. An excitation system (110) for regulating excitation current in a generator (118), the excitation system (110) comprising: a direct current (DC) to direct current (DC) converter (120) configured to receive a first DC voltage input and convert the first DC voltage input to a second DC voltage output; an automatic voltage regulator (AVR) (122) coupled to the DC to DC converter (120), the AVR (122) configured to: receive the second DC voltage output from the DC to DC converter (120); control the second DC voltage output provided to the generator (118) for regulating the excitation current in the generator (118), wherein the second DC voltage output is controlled based on an output voltage of the generator (118) to maintain the output voltage at a predetermined output voltage.

2. The excitation system (110) as claimed in claim 1, wherein the DC to DC converter (120) is configured to receive the first DC voltage input from a DC power battery source (114) included in a generator set starting system (104).

3. The excitation system (110) as claimed in claim 1, wherein the first DC voltage input is a constant voltage independent of the output voltage of the generator (118).

4. The excitation system (110) as claimed in claim 1, wherein the second DC voltage output is different from the first DC voltage input and corresponds to a step up voltage level or a step down voltage level of the first DC voltage input depending upon an excitation requirement of the generator (118).

5. The excitation system (110) as claimed in claim 1, wherein the AVR (122) is configured to control the second DC voltage output based on adifference between the output voltage of the generator (118) and the predetermined output voltage.

6. A method (200) for regulating excitation current in a generator (118), the method comprising: receiving (202), by a direct current (DC) to direct current (DC) converter (120), a first DC voltage input; converting (204), by the DC to DC converter (120), the first DC voltage input to a second DC voltage output; receiving (206), by an automatic voltage regulator (AVR) (122), the second DC voltage output from the DC to DC converter (120); controlling (208), by the AVR (122), the second DC voltage output provided to the generator (118) for regulating the excitation current in the generator (118), wherein the second DC voltage output is controlled based on an output voltage of the generator (118) to maintain the output voltage at a predetermined output voltage.

7. The method (200) as claimed in claim 6, wherein the first DC voltage input is received from a DC power battery source (114) included in a generator set starting system (104).

8. The method (200) as claimed in claim 6, wherein the first DC voltage input is a constant voltage independent of the output voltage of the generator (118).

9. The method (200) as claimed in claim 6, wherein the second DC voltage output is different from the first DC voltage input and corresponds to a step up voltage level or a step down voltage level of the first DC voltage input depending upon an excitation requirement of the generator (118).

10. The method (200) as claimed in claim 6, wherein the second DC voltage output is controlled based on a difference between the output voltage of the generator (118) and the predetermined output voltage.

11. A generator system (100), comprising: a direct current (DC) power battery source (114) configured to provide a first DC voltage input; a generator (118) configured to provide an output voltage; and an excitation system (110) for regulating excitation current in the generator (118), the excitation system (110) including: a direct current (DC) to direct current (DC) converter (120) configured to receive the first DC voltage input and convert the first DC voltage input to a second DC voltage output; an automatic voltage regulator (AVR) (122) coupled to the DC to DC converter (120), the AVR (122) configured to: receive the second DC voltage output from the DC to DC converter (120); control the second DC voltage output provided to the generator (118) for regulating the excitation current in the generator (118), wherein the second DC voltage output is controlled based on the output voltage of the generator (118) to maintain the output voltage at a predetermined output voltage.

12. The generator system (100) as claimed in claim 11, wherein the DC to DC converter (120) is configured to receive the first DC voltage input from a DC power battery source (114) included in a generator set starting system (104).

13. The generator system (100) as claimed in claim 11, wherein the first DC voltage input is a constant voltage independent of the output voltage of the generator (118).

14. The generator system (100) as claimed in claim 11, wherein the second DC voltage output is different from the first DC voltage input and corresponds to a step up voltage level or a step down voltage level of the first DC voltage input depending upon an excitation requirement of the generator (118).

15. The generator system (100) as claimed in claim 11, wherein the AVR (122) is configured to control the second DC voltage output based on a difference between the output voltage of the generator (118) and the predetermined output voltage.

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