Description:FIELD OF INVENTION
[0001] Embodiments of the present disclosure relate to a field of power systems and more particularly to an apparatus to perform power factor correction in a power system.
BACKGROUND
[0002] Power factor correction refers to a process of improving power factor of a power system. The power system includes generators, power lines and various electrical loads. The power factor is a measure of how effectively electrical power is being converted into useful work. The power factor of unity is considered ideal, indicating that the electrical power is completely being transformed into useful work. The Power factor correction is relevant in industrial systems where the power factor may deviate from unity due to inductive loads such as motors, transformers, fluorescent lights, and the like.
[0003] Traditionally, the power factor correction is carried out by several techniques, including switching of discrete capacitor banks and utilizing an active front-end compensation technique. The switching of discrete capacitor banks adds capacitive load in steps to counteract the inductive loads. However, the switching of discrete capacitor banks fails to achieve a required power factor since the capacitive load is added in steps, resulting in coarse adjustments. Further, overloading the discrete capacitor banks may damage the discrete capacitors, thereby increasing an associated maintenance cost.
[0004] The active front-end compensation technique is capable of providing fine and fast adjustments in the power factor. However, the extent of compensation capable of being provided by the active front-end compensation technique is limited by capacity of variable capacitors associated with the active front-end compensation technique, thereby making the active front-end compensation expensive. Also, significant response time is required for the switching of discrete capacitor banks and for performing the active front-end compensation technique, thereby making the power factor correction inefficient.
[0005] Hence, there is a need for an improved apparatus to perform power factor correction in a power system to address the aforementioned issue(s).
OBJECTIVE OF THE INVENTION
[0006] An objective of the invention is to provide an apparatus to perform power factor correction in a power system by switching one or more fixed capacitors and one or more variable capacitors connected to a power line.
BRIEF DESCRIPTION
[0007] In accordance with an embodiment of the present disclosure, an apparatus to perform power factor correction in a power system is provided. The apparatus includes one or more fixed capacitors connected to a power line through a corresponding first control switch. The one or more fixed capacitors are adapted to provide first leading current to the power line. The apparatus also includes one or more variable capacitors positioned adjacent to the one or more fixed capacitors and connected to the power line through a corresponding second control switch. The one or more variable capacitors are adapted to provide second leading current to the powerline. The apparatus also includes a control unit connected to the one or more variable capacitors, the one or more fixed capacitors, and the powerline. The control unit is adapted to calculate power factor of the powerline based on voltage and current measured from the powerline. The control unit is also adapted to identify a leading current requirement based on an error evaluated using the power factor calculated and a required power factor. The control unit is further adapted to evaluate an amount of the first leading current capable of being provided by the one or more fixed capacitors without exceeding the leading current requirement identified. The control unit is also adapted to evaluate the amount of the second leading current capable of being provided by the one or more variable capacitors to bridge a difference between the leading current requirement and the amount of the first leading current evaluated. The control unit is also adapted to generate one or more first switching signals and one or more second switching signals based on the amount of the first leading current and the amount of the second leading current respectively. The control unit is further adapted to trigger the corresponding first control switch with the one or more first switching signals to provide the first leading current equivalent to the amount of the first leading current evaluated to the powerline from the one or more fixed capacitors. The control unit is also adapted to trigger the corresponding second control switch with the one or more second switching signals to provide the second leading current equivalent to the amount of the second leading current evaluated to the powerline from the one or more variable capacitors, thereby performing the exact power factor correction in the power system.
[0008] To further clarify the advantages and features of the present disclosure, a more explicit description of the disclosure will follow by reference to specific embodiments thereof, which are illustrated in the appended figures. It is to be appreciated that these figures depict typical embodiments of the disclosure and are therefore not to be considered limiting in scope. The disclosure will be described and explained with additional details with the appended figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The disclosure will be described and explained with additional specificity and detail with the accompanying figures in which:
[0010] FIG. 1 is a schematic representation of an apparatus to perform power factor correction in a power system in accordance with an embodiment of the present disclosure;
[0011] FIG. 2 is a schematic representation of another embodiment of the apparatus of FIG. 1, depicting a cooling unit in accordance with an embodiment of the present disclosure;
[0012] FIG. 3 is a schematic representation of one embodiment of the apparatus of FIG. 1, depicting a front view of an enclosure of the apparatus in accordance with an embodiment of the present disclosure; and
[0013] FIG. 4 is a schematic representation of another embodiment of the apparatus of FIG. 1, depicting a side view of the enclosure in accordance with an embodiment of the present disclosure.
[0014] Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein.
DETAILED DESCRIPTION
[0015] To promote an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the disclosure as would normally occur to those skilled in the art are to be construed as being within the scope of the present disclosure.
[0016] The terms ``comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices or sub-systems or elements or structures or components preceded by "comprises... a'' does not, without more constraints, preclude the existence of other devices, sub-systems, elements, structures, components, additional devices, additional sub-systems, additional elements, additional structures, or additional components. Appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but not necessarily do, all refer to the same embodiment.
[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. The system, methods, and examples provided herein are only illustrative and not intended to be limiting.
[0018] In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings. The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
[0019] In the discussion that follows, references will be made to “first control switch”, and “second control switch” with reference to an entity (switch) that is associated with each of the one or more fixed capacitors and one or more variable capacitors. In the discussion that follows, references will be made to “first leading current”, and “second leading current” with reference to current provided by the one or more fixed capacitors and one or more variable capacitors respectively. In the discussion that follows, references will be made to “first switching signals”, and “second switching signals” with reference to switching signals provided by a control unit to the one or more fixed capacitors and one or more variable capacitors respectively.
[0020] Embodiments of the present disclosure relate to an apparatus to perform power factor correction in a power system. The apparatus includes one or more fixed capacitors connected to a power line through a corresponding first control switch. The one or more fixed capacitors are adapted to provide first leading current to the power line. The apparatus also includes one or more variable capacitors positioned adjacent to the one or more fixed capacitors and connected to the power line through a corresponding second control switch. The one or more variable capacitors are adapted to provide second leading current to the powerline. The apparatus also includes a control unit connected to the one or more variable capacitors, the one or more fixed capacitors, and the powerline. The control unit is adapted to calculate power factor of the powerline based on voltage and current measured from the powerline. The control unit is also adapted to identify a leading current requirement based on an error evaluated using the power factor calculated and a required power factor. The control unit is further adapted to evaluate an amount of the first leading current capable of being provided by the one or more fixed capacitors without exceeding the leading current requirement identified. The control unit is also adapted to evaluate the amount of the second leading current capable of being provided by the one or more variable capacitors to bridge a difference between the leading current requirement and the amount of the first leading current evaluated. The control unit is also adapted to generate one or more first switching signals and one or more second switching signals based on the amount of the first leading current and the amount of the second leading current respectively. The control unit is further adapted to trigger the corresponding first control switch with the one or more first switching signals to provide the first leading current equivalent to the amount of the first leading current evaluated to the powerline from the one or more fixed capacitors. The control unit is also adapted to trigger the corresponding second control switch with the one or more second switching signals to provide the second leading current equivalent to the amount of the second leading current evaluated to the powerline from the one or more variable capacitors, thereby performing power factor correction in the power system.
[0021] FIG. 1 is a schematic representation of an apparatus (10) to perform power factor correction in a power system in accordance with an embodiment of the present disclosure. In one embodiment, the power system may include a generator (120), a load (130), and a power line (30) feeding the load (130) from the generator (120). The apparatus (10) includes one or more fixed capacitors (20) connected to the power line (30) through a corresponding first control switch (40). In some embodiments, the one or more fixed capacitors (20) may include at least one of power factor improvement capacitors, polypropylene film capacitors, and ceramic capacitors. In one embodiment, the corresponding first control switch (40) may include a thyristor. The one or more fixed capacitors (20) are adapted to provide first leading current to the power line (30).
[0022] Further, the apparatus (10) includes one or more variable capacitors (50) positioned adjacent to the one or more fixed capacitors (20) and connected to the power line (30) through a corresponding second control switch (60). In one embodiment, the second control switch (60) may include an integrated gate bipolar transistor. The one or more variable capacitors (50) are adapted to provide second leading current to the power line (30). In one embodiment, the one or more fixed capacitors (20) and the one or more variable capacitors (50) may be connected in parallel to the power line (30). In some embodiments, the power line (30) may include a single phase power line (30). In one embodiment, the power line (30) may include a poly phase power line (30).
[0023] Furthermore, the apparatus (10) also includes a control unit (70) connected to the one or more variable capacitors (50), the one or more fixed capacitors (20), and the power line (30). The control unit (70) is adapted to calculate power factor of the power line (30) based on voltage and current measured from the power line (30). In one embodiment, the control unit (70) may be adapted to measure the voltage and current from the power line (30) using potential transformer and a hall sensor respectively. The control unit (70) is also adapted to identify a leading current requirement based on an error evaluated using the power factor calculated and a required power factor.
[0024] Moreover, the control unit (70) is further adapted to evaluate an amount of the first leading current capable of being provided by the one or more fixed capacitors (20) without exceeding the leading current requirement identified. The control unit (70) is also adapted to evaluate the amount of the second leading current capable of being provided by the one or more variable capacitors (50) to bridge a difference between the leading current requirement and the amount of the first leading current evaluated.
[0025] Additionally, the control unit (70) is adapted to generate one or more first switching signals and one or more second switching signals based on the amount of the first leading current and the amount of the second leading current evaluated respectively. The control unit (70) is further adapted to trigger the corresponding first control switch (40) with the one or more first switching signals to provide the first leading current equivalent to the amount of the first leading current evaluated to the power line (30) from the one or more fixed capacitors (20).
[0026] Also, in one embodiment, the control unit (70) may be adapted to trigger the corresponding first control switch (40) based on an operating time of the one or more fixed capacitors associated. In such an embodiment, the control unit (70) may be adapted to estimate the operating time of each of the one or more fixed capacitors (20) through a corresponding timer (not shown in FIG. 1) associated with the each of the one or more fixed capacitors (20). The control unit (70) may trigger the corresponding first control switch (40) associated with the one or more fixed capacitors (20) having the operational time less than a predefined threshold. The control unit (70) is also adapted to trigger the corresponding second control switch (60) with the one or more second switching signals to provide the second leading current equivalent to the amount of the second leading current evaluated to the power line (30) from the one or more variable capacitors (50), thereby performing power factor correction in the power system.
[0027] FIG. 2 is a schematic representation of another embodiment of the apparatus (10) of FIG. 1, depicting a cooling unit (80) in accordance with an embodiment of the present disclosure. In one embodiment, the apparatus (10) may include a cooling unit (80) comprising a heat sink (90) attached to the control unit (70). In such an embodiment, the heat sink (90) is adapted to absorb the heat energy from the control unit (70) enclosed by an enclosure (140). In one embodiment, the heat sink (90) may include a plurality of projected fins (100) on an external periphery of the heat sink (90). In some embodiments, the cooling unit (80) may also include a fan (110) positioned adjacent to the heat sink (90). In such an embodiment, the fan (110) may be adapted to blow air axially onto the plurality of projected fins (100) to radiate the heat energy absorbed by the heat sink (90) to a surrounding environment.
[0028] FIG. 3 is a schematic representation of one embodiment of the apparatus (10) of FIG. 1, depicting a front view of the enclosure (140) of the control unit (70) in accordance with an embodiment of the present disclosure. In one embodiment, the enclosure (140) may be adapted to protect the control unit (70) from an external environment. The corresponding first control switch (40), the corresponding second control switch (60) and a plurality of resistors (150) are positioned in the enclosure (140). In one embodiment, the corresponding first control switch (40) may be associated with a corresponding driver (160).
[0029] FIG. 4 is a schematic representation of another embodiment of the apparatus (10) of FIG. 1, depicting a side view of the enclosure (140) in accordance with an embodiment of the present disclosure. In a specific embodiment, the heat sink (90) may be attached to the enclosure via a seal (170).
[0030] Various embodiments of the apparatus to perform power factor correction in a power system described above enable various advantages. The control unit is capable of switching the one or more fixed capacitors and the one or more variable capacitors simultaneously to meet the leading current requirement identified, thereby performing accurate power factor correction. Switching time of the first control switch and the second control switch are very less, thereby achieving faster response. The control unit is capable of switching the one or more fixed capacitors based on the operating time of each of the one or more fixed capacitors to prevent overloading of the one or more fixed capacitors, thereby increasing life of the one or more fixed capacitors along with reducing the maintenance cost associated. The cooling unit provided is capable of cooling the first control switch, the second control switch and the control unit, thereby reducing the temperature rise within the control.
[0031] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the disclosure and are not intended to be restrictive thereof. While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended.
[0032] The figures and the forgoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, the order of processes described herein may be changed and is not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all the acts need to be necessarily performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples.
, Claims:1. An apparatus (10) to perform power factor correction in a power system comprising:
characterized in that:
one or more fixed capacitors (20) connected to a power line (30) through a corresponding first control switch (40), wherein the one or more fixed capacitors (20) are adapted to provide first leading current to the power line (30);
one or more variable capacitors (50) positioned adjacent to the one or more fixed capacitors (20) and connected to the power line (30) through a corresponding second control switch (60), wherein the one or more variable capacitors (50) are adapted to provide second leading current to the power line (30);
a control unit (70) connected to the one or more variable capacitors (50), the one or more fixed capacitors (20), and the power line (30), wherein the control unit (70) is adapted to:
calculate power factor of the power line (30) based on voltage and current measured from the power line (30);
identify a leading current requirement based on an error evaluated using the power factor calculated and a required power factor;
evaluate an amount of the first leading current capable of being provided by the one or more fixed capacitors (20) without exceeding the leading current requirement identified;
evaluate the amount of the second leading current capable of being provided by the one or more variable capacitors (50) to bridge a difference between the leading current requirement and the amount of the first leading current evaluated;
generate one or more first switching signals and one or more second switching signals based on the amount of the first leading current and the amount of the second leading current respectively;
trigger the corresponding first control switch (40) with the one or more first switching signals to provide the first leading current equivalent to the amount of the first leading current evaluated to the power line (30) from the one or more fixed capacitors (20); and
trigger the corresponding second control switch (60) with the one or more second switching signals to provide the second leading current equivalent to the amount of the second leading current evaluated to the power line (30) from the one or more variable capacitors (50), thereby performing power factor correction in the power system.
2. The apparatus (10) as claimed in claim 1, wherein the corresponding first control switch (40) comprises a thyristor.
3. The apparatus (10) as claimed in claim 1, wherein the corresponding second control switch (60) comprises an integrated gate bipolar transistor.
4. The apparatus (10) as claimed in claim 1, wherein the one or more fixed capacitors (20) and the one or more variable capacitors (50) are connected in parallel to the power line (30).
5. The apparatus (10) as claimed in claim 1, wherein the power line (30) comprises a single phase power line (30).
6. The apparatus (10) as claimed in claim 1, wherein the power line (30) comprises a poly phase power line (30).
7. The apparatus (10) as claimed in claim 1, wherein the control unit (70) is adapted to measure the voltage and current from the power line (30) using potential transformer and a hall sensor respectively.
8. The apparatus (10) as claimed in claim 1, wherein the control unit (70) is adapted to trigger the corresponding first control switch (40) based on an on operating time of the one or more fixed capacitors associated, wherein the control unit (70) is adapted to estimate the operating time of each of the one or more fixed capacitors (20) through a corresponding timer associated with the each of the one or more fixed capacitors (20).
9. The apparatus (10) as claimed in claim 1, wherein the one or more fixed capacitors (20) comprises at least one of power factor improvement capacitors, polypropylene film capacitors, and ceramic capacitors.
10. The apparatus (10) as claimed in claim 1, comprising a cooling unit (80) comprises:
a heat sink (90) attached to the control unit (70), wherein the heat sink (90) is adapted to absorb the heat energy from the control unit (70), wherein the heat sink (90) comprises a plurality of projected fins (100) on an external periphery of the heat sink (90); and
a fan (110) positioned adjacent to the heat sink (90), wherein the fan (110) is adapted to blow air axially onto the plurality of projected fins (100) to radiate the heat energy absorbed by the heat sink (90) to a surrounding environment.

Dated this 31st day of January 2024

Signature

Jinsu Abraham
Patent Agent (IN/PA-3267)
Agent for the Applicant