Claims:
1. A method of deriving inverter output phase voltage in a circuit, said method comprising the steps of:
obtaining switching information pertaining to DC link voltage of an inverter;
obtaining DC link voltage information; and
deriving said inverter output phase voltage based on a combination of said obtained switching information and said DC link voltage information.

2. The method of claim 1, wherein said switching information pertains to IGBT switching information.

3. The method of claim 1, wherein said circuit is operatively coupled with a drive for motor control.

4. The method of claim 1, wherein said switching information is obtained based on sensing of switch condition that is ON during a defined period, wherein based on said obtained switching information, the inverter output phase voltage for the defined period is obtained.

5. The method of claim 4, wherein the step of obtaining switching information for the defined period is integrated for an entire cycle, based on which output phase voltage for the said entire cycle of the inverter is obtained.

6. The method of claim 1, wherein said switching information comprises switching condition for three phase motor control to maintain desired phase difference.

7. The method of claim 1, wherein VAN, VBN, and VCN represent pole voltages with N being the DC link mid-point, and wherein VAn, VBn, and VCn represent phase voltages of the inverter with n being floating neutral point of motor such that for a balanced system:
VAn + VBn + VCn = 0
VAn = VAN - VnN
VBn = VBN - VnN
VCn = VCN - VnN
, based on which pole voltages can be equated as VAN + VBN + VCN - 3VvN = 0, making VnN = 1/3 (VAN + VBN + VCN)
giving:

,wherein VAN is computed as Switch S11 * VDC, where VDC is the DC link voltage and S11 is top phase A switch for the inverter,
,wherein VBN is computed as Switch S21 * VDC, where S21 is top phase B switch for the inverter, and
,wherein VCN is computed as Switch S31 * VDC, where S31 is top phase C switch for the inverter,

8. The method of claim 7, wherein the DC link voltage along with the sinusoidal switching signals are provided for filtering and signal conditioning and then phase voltages are obtained.

9. The method of claim 8, wherein calculated phase voltage is instantaneous and used to obtain its RMS and average values i.e. VPHASEA, VPHASEB, and VPHASEC are given as input to the RMS block, based on which line voltages VAB, VBC, and VAC are derived from phase voltage values.

10. A system for deriving inverter output phase voltage in a circuit, said system comprising:
a 3 phase inverter block configured to output DC link voltage information along with switching information pertaining to DC link voltage of an inverter; and
a control unit configured to derive said inverter output phase voltage based on a combination of said obtained switching information and said DC link voltage information.
, Description:
TECHNICAL FIELD
[0001] The present disclosure relates to the field of inverter, and more specifically relates to, a system for deriving inverter output phase voltage in a circuit Variable Frequency Drive (VFD) by using an inverter DC link and IGBT switching information.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Power electronics is a technology that facilitates electrical energy conversion between source and load based on the combined functionality of energy systems, electronics and control. The use of power electronics has been widely seen in various applications, such as aerospace, military, automotive, computing etc., for proper and energy efficient operation.
[0004] In power electronics systems, the conversion process begins when the controller, which is a low-power digital or analog electronic circuit, operates the power converter/switches according to a modulation strategy.
[0005] Of all the ways solar electricity benefits the people on Earth, none makes as much difference in the daily lives as pumping water. By providing water for irrigation or potable water have obvious benefits for people in rural areas and especially for those in developing nations. The proper choice is determined by application specific factors like how much water is required and whether the water should be available at night or just during high sun hours.
[0006] For high amounts of water, a large AC pump is usually required. These pumps require well regulated 3 phase AC voltage and current. By using an AC variable speed controller called a Variable Frequency Drive (VFD) or Adjustable Speed Drive (ASD) the pump motor will have the proper voltage and current. The trick is to supply DC from the PV array directly into the DC bus inside the VFD. The normal AC input is not used. As the sun rises and PV voltage and current increase, some VFD products will accept the input and when the power is high enough, it will start the pump. The PV array must be large enough to provide enough power to start the pump with including the head of water. The size of the PV array required for this method can be very expensive.
[0007] In the conventional method or system, output voltage, DC link voltage and DC current measured by measurement sensor. However, in the prior-art, there is a requirement of separate phase voltage sensor used along with DC link current and voltage sensor due to which circuit becomes complex and bulky.
[0008] Whereas there is certainly nothing wrong with existing system or processor, nonetheless, there still exists a need to provide an efficient, effective, reliable, and improved system of output phase voltage derivation for solar Variable Frequency Drive (VFD) by using an inverter DC link and IGBT switching information. Further, there is a need of a system and device for phase voltage reconstruction from DC link voltage and IGBT switching information. Furthermore, there is a need of circuit or system which does not requires extra sensor in the inverter output required for calculation of the output voltage and hence within the same hardware the output voltage information is obtained.
[0009] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[00010] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about”. Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[00011] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[00012] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[00013] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.

OBJECTS OF THE INVENTION
[00014] An object of the present disclosure is to provide a system of output phase voltage derivation for solar Variable Frequency Drive (VFD) by using an inverter DC link and IGBT switching information.
[00015] Another object of the present disclosure is to provide a system and device for phase voltage reconstruction from DC link voltage and IGBT switching information.
[00016] Another object of the present disclosure is to provide a circuit or system which does not requires extra sensor in the inverter output required for calculation of the output voltage and hence within the same hardware the output voltage information is obtained.

SUMMARY
[00017] The present disclosure relates to the field of inverter, and more specifically relates to, a system for deriving inverter output phase voltage in a circuit Variable Frequency Drive (VFD) by using an inverter DC link and IGBT switching information.
[00018] Embodiments of the present disclosure provide an efficient, effective, reliable, and inverter. Further, a system of output phase voltage derivation for solar Variable Frequency Drive (VFD) by using an inverter DC link and IGBT switching information.
[00019] Accordingly, an aspect of the present disclosure relates to a method of deriving inverter output phase voltage in a circuit. The method includes the steps of obtaining switching information pertaining to DC link voltage of an inverter; obtaining DC link voltage information; and deriving said inverter output phase voltage based on a combination of said obtained switching information and said DC link voltage information.
[00020] In an aspect, switching information can pertain to IGBT switching information.
[00021] In an aspect, circuit can be operatively coupled with a drive for motor control.
[00022] In an aspect, switching information can be obtained based on sensing of switch condition that is ON during a defined period, wherein based on said obtained switching information, the inverter output phase voltage for the defined period is obtained.
[00023] In an aspect, the step of obtaining switching information for the defined period can be integrated for an entire cycle, based on which output phase voltage for the said entire cycle of the inverter is obtained.
[00024] In an aspect, switching information can include switching condition for three phase motor control to maintain desired phase difference.
[00025] In an aspect, VAN, VBN, and VCN represent pole voltages with N being the DC link mid-point, and wherein VAn, VBn, and VCn represent phase voltages of the inverter with n being floating neutral point of motor such that for a balanced system:
VAn + VBn + VCn = 0
VAn = VAN - VnN
VBn = VBN - VnN
VCn = VCN - VnN
, based on which pole voltages can be equated as VAN + VBN + VCN - 3VvN = 0, making VnN = 1/3 (VAN + VBN + VCN)
giving:

,wherein VAN is computed as Switch S11 * VDC, where VDC is the DC link voltage and S11 is top phase A switch for the inverter,
,wherein VBN is computed as Switch S21 * VDC, where S21 is top phase B switch for the inverter, and
,wherein VCN is computed as Switch S31 * VDC, where S31 is top phase C switch for the inverter,
[00026] In an aspect, the DC link voltage along with the sinusoidal switching signals can be provided for filtering and signal conditioning and then phase voltages are obtained.
[00027] In an aspect, calculated phase voltage can be instantaneous and used to obtain its RMS and average values i.e. VPHASEA, VPHASEB, and VPHASEC are given as input to the RMS block, based on which line voltages VAB, VBC, and VAC are derived from phase voltage values.
[00028] An aspect of the present disclosure relates to a system for deriving inverter output phase voltage in a circuit. In an aspect, the system can include a 3 phase inverter block and control unit. In another aspect, the 3 phase inverter block can be configured to output DC link voltage information along with switching information pertaining to DC link voltage of an inverter. In another aspect, the control unit can be configured to derive said inverter output phase voltage based on a combination of said obtained switching information and said DC link voltage information.
[00029] In contrast to the conventional system, the present disclosure provides motor a system for deriving inverter output phase voltage in a circuit Variable Frequency Drive (VFD) by using an inverter DC link and IGBT switching information. Further, in contrast to the existing system, the present invention provides a system and device for phase voltage reconstruction from DC link voltage and IGBT switching information. Furthermore, in contrast to the existing system, the present invention or system does not requires extra sensor in the inverter output required for calculation of the output voltage and hence within the same hardware the output voltage information is obtained.
[00030] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[00031] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The diagrams are for illustration only, which thus is not a limitation of the present disclosure, and wherein:
[00032] FIG. 1 illustrates a solar pump drive, in accordance with an exemplary embodiment of the present disclosure.
[00033] FIG. 2 illustrates a typical line-line output voltage of the three phase inverter/VFD, in accordance with another exemplary embodiment of the present disclosure.
[00034] FIG. 3 illustrates a phase voltage reconstruction mechanism for three phase inverter/VFD, in accordance with another exemplary embodiment of the present disclosure.
[00035] FIG. 4 illustrates a control block for phase voltage reconstruction, in accordance with another exemplary embodiment of the present disclosure.
[00036] FIG. 5 illustrates flow chart for calculating the phase voltage from DC link and switching state of the inverter information, in accordance with another exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION
[00037] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.
[00038] If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[00039] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[00040] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. These exemplary embodiments are provided only for illustrative purposes and so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. The invention disclosed may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Various modifications will be readily apparent to persons skilled in the art. The general principles defined herein may be applied to other embodiments and applications without departing from the scope of the invention. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure). Also, the terminology and phraseology used is for the purpose of describing exemplary embodiments and should not be considered limiting. Thus, the present invention is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed. For purpose of clarity, details relating to technical material that is known in the technical fields related to the invention have not been described in detail so as not to unnecessarily obscure the present invention.
[00041] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[00042] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[00043] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[00044] The present disclosure relates to the field of inverter, and more specifically relates to, a system for deriving inverter output phase voltage in a circuit Variable Frequency Drive (VFD) by using an inverter DC link and IGBT switching information.
[00045] Embodiments of the present disclosure provide an efficient, effective, reliable, and inverter. Further, a system of output phase voltage derivation for solar Variable Frequency Drive (VFD) by using an inverter DC link and IGBT switching information.
[00046] Accordingly, an aspect of the present disclosure relates to a method of deriving inverter output phase voltage in a circuit. The method includes the steps of obtaining switching information pertaining to DC link voltage of an inverter; obtaining DC link voltage information; and deriving said inverter output phase voltage based on a combination of said obtained switching information and said DC link voltage information.
[00047] In an aspect, switching information can pertain to IGBT switching information.
[00048] In an aspect, circuit can be operatively coupled with a drive for motor control.
[00049] In an aspect, switching information can be obtained based on sensing of switch condition that is ON during a defined period, wherein based on said obtained switching information, the inverter output phase voltage for the defined period is obtained.
[00050] In an aspect, the step of obtaining switching information for the defined period can be integrated for an entire cycle, based on which output phase voltage for the said entire cycle of the inverter is obtained.
[00051] In an aspect, switching information can include switching condition for three phase motor control to maintain desired phase difference.
[00052] In an aspect, VAN, VBN, and VCN represent pole voltages with N being the DC link mid-point, and wherein VAn, VBn, and VCn represent phase voltages of the inverter with n being floating neutral point of motor such that for a balanced system:
VAn + VBn + VCn = 0
VAn = VAN - VnN
VBn = VBN - VnN
VCn = VCN - VnN
, based on which pole voltages can be equated as VAN + VBN + VCN - 3VnN = 0, making VnN = 1/3 (VAN + VBN + VCN)
giving:

,wherein VAN is computed as Switch S11 * VDC, where VDC is the DC link voltage and S11 is top phase A switch for the inverter, (which means as in FIG. 3 S12 i.e. complimentary of S11 will be OFF) i.e., when S11 is ON its complimentary switch is off-TOP and BOTTOM switch are complimentary to each other.
,wherein VBN is computed as Switch S21 * VDC, where S21 is top phase B switch for the inverter(which means as in FIG. 3 S22 i.e. complimentary of S11 will be OFF.)
, and
,wherein VCN is computed as Switch S31 * VDC, where S31 is top phase C switch for the inverter, (which means as in FIG. 3 S32 i.e. complimentary of S11 will be OFF.)
[00053] In an aspect, the DC link voltage along with the sinusoidal switching signals can be provided for filtering and signal conditioning and then phase voltages are obtained.
[00054] In an aspect, calculated phase voltage can be instantaneous and used to obtain its RMS and average values i.e. VPHASEA, VPHASEB, and VPHASEC are given as input to the RMS block, based on which line voltages VAB, VBC, and VAC are derived from phase voltage values.
[00055] An aspect of the present disclosure relates to a system for deriving inverter output phase voltage in a circuit. In an aspect, the system can include a 3 phase inverter block and control unit. In another aspect, the 3 phase inverter block can be configured to output DC link voltage information along with switching information pertaining to DC link voltage of an inverter. In another aspect, the control unit can be configured to derive said inverter output phase voltage based on a combination of said obtained switching information and said DC link voltage information.
[00056] In contrast to the conventional system, the present disclosure provides motor a system for deriving inverter output phase voltage in a circuit Variable Frequency Drive (VFD) by using an inverter DC link and IGBT switching information. Further, in contrast to the existing system, the present invention provides a system and device for phase voltage reconstruction from DC link voltage and IGBT switching information. Furthermore, in contrast to the existing system, the present invention or system does not requires extra sensor in the inverter output required for calculation of the output voltage and hence within the same hardware the output voltage information is obtained.
[00057] FIG. 1 illustrates a solar pump drive, in accordance with an exemplary embodiment of the present disclosure.
[00058] In an embodiment, the solar pump drive for deriving inverter output phase voltage. The solar pump drive can include a 3 phase inverter block 104 configured to output DC link voltage information along with switching information pertaining to DC link voltage of an inverter; and a control unit 102 configured to derive said inverter output phase voltage based on a combination of said obtained switching information and said DC link voltage information.
[00059] FIG. 2 illustrates a typical line-line output voltage of the three phase inverter/VFD, in accordance with another exemplary embodiment of the present disclosure.
[00060] For three phases inverter in motor control application sensing output voltage can be a challenge considering the PWM output i.e. pulses of voltages with high switching frequency as shown in FIG .2. Sensing the output voltage in the inverter can be required to protect the inverter as well as motor in cased of over load, output voltage unbalance due to motor abnormal behavior. Detecting this condition will facilitate the protection of motor as well as inverter.
[00061] Inverter output voltage is obtained from switching of the DC link voltage of the inverter. By sensing the switch condition which is ON during a particular period the output voltage information for that particular time instant can be obtained and integrating this process for entire cycle output voltage of the inverter can be obtained.
[00062] FIG. 3 illustrates a phase voltage reconstruction mechanism for three phase inverter/VFD, in accordance with another exemplary embodiment of the present disclosure.
[00063] The three phase output voltage of the inverter would be 120° apart in phases and this is provided by inverter switching for three phase motor control to maintain the phase difference. Thus switch condition along with the DC link voltage Vdc information will be helpful for providing the output phase voltage reconstruction or information. N is the DC link mid-point and VAN, VBN, VCN are the pole voltage. n is the floating neutral point of the motor and Van,VBn,VCn are the phase voltage of the inverter. For balanced three phase system as in FIG. 2.
VAn+VBn+VCn = 0 -1)
VAn = VAN – VnN -2)
VBn = VBN – VnN -3)
VCn = VCN – VnN -4)
From above equations:
VAN+VBN+VCN – 3VnN =0; and hence
Using above equation in 2, 3, and 4 following can be analyzed:
For three phase inverter phase voltage can be calculated as:
-5)
-6)
-7)
[00064] VAN, VBN, VCN considered as when e.g. For VAN upper switch S1 as shown in FIG. 3 is ON i.e. VAN = S11*VDC where VDC is the DC link voltage and S11 is the Top phase A switch of the inverter module. Similarly for other pole voltages values can be derived.
[00065] FIG. 4 illustrates a control block for phase voltage reconstruction, in accordance with another exemplary embodiment of the present disclosure.
[00066] The DC link voltage along with the sinusoidal switching signals are provided for filtering and signal conditioning and then phase voltage are obtained with performing the calculations with above equations. The calculated phase voltage is instantaneous and to obtain its RMS and average value i.e. VPHASEA, B, C are given input to the RMS Block.
[00067] From above analysis the line voltages i.e. VAB, VBC. VCA can be derived from phase voltage values. Entire 112 blocks i.e. FIG.4 has been implemented within the DSP (digital signal processor) the output phase voltage provides user with the information of the motor voltage. This information also can be useful for calculating motor power, active power etc.
[00068] In an embodiment, for three phases inverter in motor control application sensing output voltage can be a challenge considering the PWM output i.e. pulses of voltages with high switching frequency as shown in FIG .2. Sensing the output voltage in the inverter can be required to protect the inverter as well as motor in cased of over load, output voltage unbalance due to motor abnormal behavior. Detecting this condition will facilitate the protection of motor as well as inverter.
[00069] Inverter output voltage is obtained from switching of the DC link voltage of the inverter. By sensing the switch condition which is ON during a particular period the output voltage information for that particular time instant can be obtained and integrating this process for entire cycle output voltage of the inverter can be obtained.
[00070] The three phase output voltage of the inverter would be 120° apart in phases and this is provided by inverter switching for three phase motor control to maintain the phase difference. Thus switch condition along with the DC link voltage Vdc information will be helpful for providing the output phase voltage reconstruction or information. N is the DC link mid-point and VAN, VBN, VCN are the pole voltage. n is the floating neutral point of the motor and Van,VBn,VCn are the phase voltage of the inverter. For balanced three phase system as in FIG. 2.
VAn+VBn+VCn = 0 -1)
VAn = VAN – VnN -2)
VBn = VBN – VnN -3)
VCn = VCN – VnN -4)
From above equations:
VAN+VBN+VCN – 3VnN =0; and hence
Using above equation in 2, 3, and 4 following can be analyzed:
For three phase inverter phase voltage can be calculated as:
-5)
-6)
-7)
[00071] VAN, VBN, VCN considered as when e.g. For VAN upper switch S1 as shown in FIG. 3 is ON i.e. VAN = S11*VDC where VDC is the DC link voltage and S11 is the Top phase A switch of the inverter module. Similarly for other pole voltages values can be derived.
[00072] The DC link voltage along with the sinusoidal switching signals are provided for filtering and signal conditioning and then phase voltage are obtained with performing the calculations with above equations. The calculated phase voltage is instantaneous and to obtain its RMS and average value i.e. VPHASEA, B, C are given input to the RMS Block.
[00073] From above analysis the line voltages i.e. VAB, VBC. VCA can be derived from phase voltage values. Entire 112 blocks i.e. FIG.4 has been implemented within the DSP (digital signal processor) the output phase voltage provides user with the information of the motor voltage. This information also can be useful for calculating motor power, active power etc.
[00074] FIG. 5 illustrates flow chart for calculating the phase voltage from DC link and switching state of the inverter information, in accordance with another exemplary embodiment of the present disclosure.
[00075] At step 502, start the inverter by switching pulses.
[00076] At step 504, check whether system is healthy or not.
[00077] At step 506, monitor VDC the DC link voltage and capture the switching instant.
[00078] At step 508, apply inverter phase voltage calculations 1, 2 and 3 and obtain VAB, VBC. VCA.
[00079] At step 510, pass VAB, VBC. VCA through RMS block to get average and RMS value of the phase voltage.
[00080] At step 512, the output of the RMS block i.e. phase voltage can be used for user display and other calculations like active power etc.
[00081] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C ….and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc. The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the scope of the appended claims.
[00082] While embodiments of the present disclosure have been illustrated and described, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the scope of the disclosure, as described in the claims.
[00083] In the description of the present specification, reference to the term "one embodiment," "an embodiments", "an example", "an instance", or "some examples" and the description is meant in connection with the embodiment or example described The particular feature, structure, material, or characteristic included in the present invention, at least one embodiment or example. In the present specification, the term of the above schematic representation is not necessarily for the same embodiment or example. Furthermore, the particular features structures, materials, or characteristics described in any one or more embodiments or examples in proper manner. Moreover, those skilled in the art can be described in the specification of different embodiments or examples are joined and combinations thereof.
[00084] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
[00085] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
[00086] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
[00087] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[00088] The present disclosure provides a system of output phase voltage derivation for solar Variable Frequency Drive (VFD) by using an inverter DC link and IGBT switching information.
[00089] The present disclosure provides a system and device for phase voltage reconstruction from DC link voltage and IGBT switching information.
[00090] The present disclosure provides a circuit or system which does not requires extra sensor in the inverter output required for calculation of the output voltage and hence within the same hardware the output voltage information is obtained.