DESC:THREE-PHASE THREE-LEVEL INVERTER SYSTEM WITH INTERLEAVED SINGLE-PHASE OUTPUT

FIELD OF INVENTION
The present invention is in the field of power converter. More particularly, the present invention relates to a three-phase three-level inverter system with interleaved single-phase output, which achieve higher throughput using interleaved topology for single-phase load, dual or multiple booster with voltage balancing capacity for medium and high-power ratings.

BACKGROUND OF INVENTION
A variety of solar photo voltaic panels are used in solar energy systems which is one of the largest sources of renewable energy. In any photovoltaic system, the inverter is the heart of the system which converts the DC power to AC power with maximum power point. The function of maximum power point, protection of circuit is done in real time using digital controllers. Advanced micro-controllers with inbuilt digital signal processing capabilities provide sophisticated real time control using mathematics intensive algorithms.

Various developments and inventions were made, and several products are available for converting DC power to AC power.

United States patent number US8184460B2 discloses a method to boost the available solar voltage and then feed the power to the three-phase grid using three level booster and I-type three level inverter circuit. Working with motor control algorithms is not claimed in patent though it is possible to control the three-phase motor using appropriate algorithm to generate PWM signals. However, this patent provides no solution for single-phase output.

United States patent number US9595862B1 discloses three-phases of phase shifted dual T-type inverter which can be connected to a three-phase isolation transformer in the grid side. Each phase uses two legs of T-Type Inverter which helps in generating 5 level output waveforms. However, the system does not have the capability to be used in pump control as the cost will be prohibitive and the feature to provide single-phase output power is not available.

United States patent number US9871379B2 discloses a structure for smart AC/DC microgrid with multiple DC power sources like Solar, Wind, Battery etc. It generates the AC output which can feed various loads. It discloses the concept of forming a microgrid with various communication networks including wireless/power line communication. However, the patent does not specify or cannot be used in pump controller or standalone/grid tied single-phase power generation.

European patent number EP2728734A1 discloses a special type mixed three level neutral point clamped inverter which improves efficiency of the Inverter by using one device structure for switching and another for conduction. The system, if adopted for pump controller applications, will result in an increased number of devices with complex control algorithms. The cost component will outpace the efficiency benefits as the power factor of the load is always lagging in pump controllers.

Japanese patent number JP2015015884A discloses multilevel inverter using cascaded cell T-type Inverter. In this case the T-type structure is used to improve the heat spreading by distributing the power loss across an increased number of devices. The structure is meant for high voltage high power motor control which is fed from multiphase secondary windings of isolation transformers resulting in multi pulse rectifier operation to reduce the line side harmonics. The structure is meant for grid operation and cannot be used for solar pump controllers.

Indian patent number 271798 discloses solar power conversion system which can be used for three-phase motor/pumping and single-phase load application. The system uses a standard two-level power conversion mechanism which consists of three half bridges for three-phase output and H bridge for single-phase output. However, the system cannot deliver full single phase output power with rated devices.

Indian patent Number 378036 discloses sinusoidal pump controller for efficient water pumping with two stage power converter topology which uses adaptive control loop with inner inductor current control loop structure. As the inverter is 2-Level type, higher volume/value filter components are required to generate clean sine waves.

Indian patent Number 393702 discloses unidirectional DC-DC converter which feeds the DC-AC converter feeding the grid and separate three-phase bridge for the motor/pump control. The system does not deliver single-phase power output. Even to feed the grid, the system needs separate power devices which are not cost effective.

Solar power generation is growing exponentially and the products available are targeted for specific single use. Single-phase grid tied inverter limited to 10kW peak power are being used in roof top solar PV application feeds the power to the grid. Solar PV string inverters with multiple MPP inputs limited to 150kW are being used to feed the power to grid and off grid solar pumping drive which is used to run the pump. Solar pumping is getting wider user acceptance enabling farmer communities to have planned irrigation and can replace the existing fossil fuel dependent diesel pump sets. As the installation of units in solar pumping is increasing, there is a strong need for a multi-application load handling power converter which can power the agrarian load applications like chaff cutter, deep freezer and other farm equipment or feeding the power to grid when pump is not in use, for which the present invention is a solution. Multiple units of single use power converters are required to power these various applications such as a pump controller for pumping and a grid tied inverter for grid feeding.

None of the prior arts discusses about a power converter which is efficient, compact, fully automatic, digitally controlled and can power the irrigation pump having Alternating Current Induction Motor (ACIM) which may be specially made for Variable Speed Drive (VFD) operation. Accordingly, there exists a need for a power converter which is efficient, compact, fully automatic, digitally controlled and can power the irrigation pump having Alternating Current Induction Motor (ACIM) which may be specially made for Variable Speed Drive (VFD) operation.

One or more of the problems of the conventional prior arts as mentioned above may be overcome by the present invention by improvements made on variable frequency drive rated high performance pumping system, traditional three phase induction and permanent magnet motor loads, traditional three-phase loads, three-phase grid feeding facility, single-phase loads, single-phase grid feeding system, highly efficient power conversion with lower harmonics and common mode leakage current, effective use of all switches of three-phase leg to achieve higher throughput using interleaved topology for single-phase load, dual or multiple booster with voltage balancing capacity for medium and high power ratings and a cost effective all in one power conversion system.

OBJECTS OF INVENTION
One or more of the problems of the conventional prior arts may be overcome by various embodiments of the system and method of the present invention.

It is the primary object of the present invention to provide a three-phase three-level single inverter system with interleaved single-phase output, which achieve higher throughput using interleaved topology for single-phase load, dual or multiple boosters with voltage balancing capacity for medium and high power ratings.

It is another object of the present invention to provide a three-phase three-level single inverter system with interleaved single-phase output, which is efficient, compact, fully automatic, digitally controlled and could power an irrigation pump having Alternating Current Induction Motor (ACIM) or Permanent Magnet Synchronous Motor (PMSM) which may be specially made for Variable Speed Drive (VFD) operation.

It is another object of the present invention to provide a three-phase three-level single inverter system with interleaved single-phase output, which provides low-harmonic, low spiky electrical power to traditional three-phase or single-phase motor loads used in agrarian applications and could be a single-phase or three-phase grid tied inverter as well.

It is another object of the present invention, wherein the three-phase three-level single inverter system with interleaved single-phase output supplies power to off-grid three-phase or single-phase loads and on-grid single or three-phase loads.

It is another object of the present invention, wherein the three-phase three-level single inverter system with interleaved single-phase output carries out hardware diagnostics and reports data remotely through a portable device.

It is another object of the present invention, wherein the portable device includes a mobile phone, tablet, laptop, and personal computer.

SUMMARY OF INVENTION
Thus, the basic aspect of the present invention is to provide a three-phase three-level inverter system with interleaved single-phase output, said system comprising:
an input power source;
a three-level voltage generation section;
an inverter stage;
a changeover with line filter stage;
a control section consists of a digital controller with Maximum Power Point Tracking (MPPT) for the voltage generation section and inverter control stage with output mode selection control unit;
a wired or wireless module; and
a portable device,
wherein the inverter stage output is fed to the changeover with filter stage,
wherein the inverter stage is made up of line frequency filters for harmonic content reduction and selection switches to modify the inverter output according to the load type selected,
wherein the changeover with filter stage provides three-phase or single-phase power output to off grid loads and three-phase or single-phase power output to grid,
wherein the digital controller based on system voltage, current and temperature feedback carries out hardware diagnostics and reports data to the portable device via the wired or wireless module, and
wherein the configuration required for hardware is based on load requirement and rating is automatically set by the digital controller.

It is another aspect of the present invention, wherein the inverter stage is a T-Type Neutral Point Clamped (T-NPC) inverter consisting of 12 switches used for DC-AC conversion.

It is another aspect of the present invention, wherein the changeover with line filter stage comprises of contactor/relays which are controlled by a digital control block of the output mode selection control unit through control signals to K1 to K5 based on user input commands from the portable device via the wired or wireless module.

It is another aspect of the present invention, wherein the three-level output voltage from the voltage generation section is directly connected to the inverter stage and appropriate gate control pulses are generated in the output mode selection control unit to produce the output with desired voltage and frequency.

It is another aspect of the present invention, wherein the output mode selection control unit consists of a signal conditioning and sensing section, a system operation mode selection processing sub section, a three-phase or single-phase voltage and current controller section used to generate control signals followed by a pulse width modulation section.

It is another aspect of the present invention, wherein the system operation mode selection processing sub section is used for load type selection as per user requirement through the wired or wireless module.

It is another aspect of the present invention, wherein the digital control block is used to appropriately select the operating modes of the three-phase or single-phase voltage, current controller section and the pulse width modulation section as per input and generates control signal for the output mode selector switch with filter stage.

It is another aspect of the present invention, wherein in single-phase output mode, said system operates as multiphase converter by utilizing all the switches of the T-NPC inverter stage and modifying output terminal connection corresponding to a single phase rated output load and a single-phase utility grid connection in the output mode selector switch with filter stage.

It is another aspect of the present invention, wherein pulse width modulation signals generated at the pulse width modulation section are phase shifted by 120º for each leg within a pulse width modulation period to utilize the switches of the inverter stage ensuring full power delivery rating in both three-phase and single-phase mode.

It is another aspect of the present invention, wherein the voltage generation section is eliminated for direct coupling if the input voltage is more than 570V and only three phase loads are to be powered.

It is another aspect of the present invention, wherein the control section consists of a signal conditioning with error signal generation section, a MPPT controller, a digital voltage controller, an input DC source selection block, a mode control section, a DC-link capacitor voltage balance controller and a pulse width modulator.

It is another aspect of the present invention, wherein the DC-link capacitor voltage balance controller monitors the DC voltage balancing across the DC-link capacitors and appropriate control action is carried out.

It is another aspect of the present invention, wherein the mode control section controls the MPPT controller and digital voltage controller based on the input source and topology used for the voltage generation section.

It is another aspect of the present invention, wherein the input power source includes a solar PV or a battery or a DC source.

BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1: illustrates a block diagram of the three-phase three-level inverter system with interleaved single-phase output according to the present invention.
Figure 2: illustrates the circuit diagram of the three-level voltage generation section and inverter stage in the three-phase three-level inverter system according to one embodiment of the present invention.

Figure 3: illustrates the enlarged view of the circuit diagram of the three-level voltage generation section as shown in Figure 2 according to one embodiment of the present invention.
Figure 4: illustrates the circuit diagram of the three-level voltage generation section and inverter stage in the three-phase three-level inverter system according to another embodiment of the present invention.
Figure 5: illustrates the enlarged view of the circuit diagram of the three-level voltage generation section as shown in Figure 4 according to another embodiment of the present invention.
Figure 6: illustrates the circuit diagram of the three-level voltage generation section and inverter stage in the three-phase three-level inverter system according to another embodiment of the present invention.
Figure 7: illustrates the enlarged view of the circuit diagram of the three-level voltage generation section as shown in Figure 6 according to another embodiment of the present invention.
Figure 8: illustrates the circuit diagram of the changeover with line filter stage in the three-phase three-level inverter system according to the present invention.
Figure 9: illustrates the block diagram of the control section of the three-phase three-level inverter system with interleaved single-phase output according to the present invention.
Figure 10: illustrates the circuit diagram of the inverter stage of the three-phase three-level inverter system according to the present invention.
Figure 11: illustrates the block diagram of the inverter control stage with output mode selection control unit of the three-phase three-level inverter system according to the present invention.
Figure 12: illustrates the graph showing the inverter control signals for single phase output mode using the three-phase three-level inverter system with interleaved single-phase output according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURES
The present invention as herein described relates to a three-phase three-level single inverter system with interleaved single-phase output, which achieve higher throughput using interleaved topology for single-phase load, dual or multiple booster with voltage balancing capacity for medium and high power ratings.

Referring to Figures 1 to 11, the three-phase three-level inverter system with interleaved single-phase output, comprises of an input power source [100]; a three-level voltage generation section [200]; an inverter stage [300]; a changeover with line filter stage [500]; a control section [400] consists of a digital controller with MPPT [410] for the voltage generation section [200] and inverter control stage [300] with output mode selection control unit [420]; a wired or wireless module [430]; and a portable device [440]. The inverter stage [300] is a T-Type Neutral Point Clamped (T-NPC) inverter consisting of 12 switches used for DC-AC conversion. Said inverter stage [300] output is fed to the changeover with filter stage [500]. The changeover with filter stage [500] provides three-phase or single-phase power output to off grid loads and three-phase or single-phase power output to grid. The changeover with line filter stage [500] provides higher flexibility for using the said three-phase three-level inverter system to modify the output section as per user need and unused system elements can be removed to make the system cost effective. The digital controller [410] based on system voltage, current and temperature feedback carries out hardware diagnostics and reports data to the portable device [440] via the wired or wireless module [430].

In a preferred embodiment of the present invention, the filter stage [500] is made up of line frequency filters for harmonic content reduction and selection switches to modify the inverter stage [300] output according to the load type selected.

In another preferred embodiment of the present invention, the configuration required for hardware is based on load requirement and rating is automatically set by the digital controller [420].

In another preferred embodiment of the present invention, the three-phase three-level single inverter system is based on either Insulated Gate Bipolar Transistor (IGBT), or Reverse Blocking Insulated Gate Bipolar Transistor (RB-IGBT), or Metal Oxide Field Effect Transistor (MOSFET), or Silicon Carbide Metal Oxide Silicon Field Effect Transistor (SiC-MOSFET), or Gallium Nitride Field Effect Transistors (GaN FET) or other similar switching power device that can provide efficiency and is cost effective.

In another preferred embodiment of the present invention, the changeover with line filter stage [500] comprises of contactor/relays which are controlled by digital control block [423] of the output mode selection control unit [420] through control signals to K1 to K5 based on user input commands from the portable device [440] via the wired or wireless module [430].

In another preferred embodiment of the present invention, the three-level output voltage from the voltage generation section [200] is directly connected to the inverter stage [300] and appropriate gate control pulses are generated in the output mode selection control unit [420] as shown in Figure 11 to produce the output with desired voltage and frequency. The output mode selection control unit [420] as shown in Figure 11 consists of a signal conditioning and sensing section [421], a system operation mode selection processing sub section [422], a three phase or single-phase voltage and current controller section [424] used to generate control signals followed by a pulse width modulation section [425]. The sub section [422] is used for load type selection as per user requirement through the wired or wireless module [8]. The digital control block [423] as shown in Figure 11 is used to appropriately select the operating modes of the three phase or single-phase voltage, current controller section [424] and the pulse width modulation section [425] as per input and generates control signal for the output mode selector switch with filter stage [500].

In another preferred embodiment of the present invention, in single-phase output mode, the system operates as multiphase converter by utilizing all the switches as shown in Figure 10 of the T-NPC inverter stage [300] and modifying output terminal connection corresponding to a single phase rated output load [900] and a single-phase utility grid connection [1000] in the output mode selector switch with filter stage [500]. In a preferred embodiment, pulse width modulation signals generated at the pulse width modulation section [425] are phase shifted by 120º as shown in Figure 12 for each leg within a pulse width modulation period to utilize the switches of the inverter stage [300] ensuring full power delivery rating in both three phase and single-phase mode.
In another preferred embodiment of the present invention, the voltage generation section [200] is eliminated for direct coupling as shown in Figure 4 if the input voltage is more than 570V and only three-phase loads are to be powered. The input voltage limitation need not be considered when the output voltage limits are not stringent as in the case of pumps.

In another preferred embodiment of the present invention, the control section [400] as shown in Figure 9 consists of a signal conditioning with error signal generation section [411], a MPPT controller [413], a digital voltage controller [415], an input DC source selection block [412], a mode control section [414], a DC-link capacitor voltage balance controller [416] and a Pulse width modulator [417]. The DC-link capacitor voltage balance controller [416] monitors the DC voltage balancing across the DC-link capacitors and appropriate control action is carried out. The mode control section [414] controls the Maximum Power Point Tracking (MPPT) controller [413] and digital voltage controller [415] based on the input source [100] and topology used for the voltage generation section [200]. In a preferred embodiment, using suitable algorithm the digital controller [410] generates PWM for G1 and G2 in the voltage generation section [200]. The algorithm with required feedback maintains voltage balance across C1 and C2 as shown in Figure 2 apart from boosting the input voltage to achieve the MPPT.

In another preferred embodiment of the present invention, using sine wave modulation or space vector modulation or proprietary algorithm, the output mode selection control unit [420] generates the required PWMs for GA1, GA2, GA3, GA4, GB1, GB2, GB3, GB4, GC1, GC2, GC3 and GC4.

In another preferred embodiment of the present invention, the input power source [100] includes a solar PV or a battery or a DC source.

Working:
For illustration:
Referring to Figures 1 to 11, the three-phase three-level inverter system comprises of an input power source [100]; a three-level voltage generation section [200]; an inverter stage [300]; a changeover with line filter stage [500]; a control section [400] consists of a digital controller with MPPT [410] for the voltage generation section [200] and inverter control stage [300] with output mode selection control unit [420]; a wired or wireless module [8]; and a portable device [440]. The inverter stage [300] is a T-Type Neutral Point Clamped (T-NPC) inverter consisting of 12 switches used for DC-AC conversion. Said inverter stage [300] output is fed to the changeover with filter stage [500]. The inverter stage [300] is made up of line frequency filters for harmonic content reduction and selection switches to modify the inverter output according to the load type selected. The changeover with filter stage [500] provides three-phase or single-phase power output to off grid loads and three-phase or single-phase power output to grid. The changeover with line filter stage [500] provides higher flexibility for using the said three-phase three-level inverter system to modify the output section as per user need and unused system elements can be removed to make the system cost effective. The digital controller [410] based on system voltage, current and temperature feedback carries out hardware diagnostics and reports data to the portable device [440] via the wired or wireless module [430]. The configuration required for hardware is based on load requirement and rating is automatically set by the digital controller [400].

Referring to Figure 8, the changeover with line filter stage [500] comprises of contactor/relays which are controlled by digital control block [423] of the output mode selection control unit [420] through control signals to K1 to K5 based on user input commands from the portable device [440] via the wired or wireless module [430]. The three-level output voltage from the voltage generation section [200] is directly connected to the inverter stage [300] and appropriate gate control pulses are generated in the output mode selection control unit [420] as shown in Figure 11 to produce the output with desired voltage and frequency. The output mode selection control unit [420] as shown in Figure 11 consists of a signal conditioning and sensing section [421], a system operation mode selection processing sub section [422], a three phase or single-phase voltage and current controller section [424] used to generate control signals followed by a pulse width modulation section [425]. The system operation mode selection processing sub section [422] is used for load type selection as per user requirement through the wired or wireless module [8]. The digital control block [423] is used to appropriately select the operating modes of the three phase or single-phase voltage, current controller section [424] and the pulse width modulation section [425] as per input and generates control signal for the output mode selector switch with filter stage [500].

In a preferred embodiment of the present invention, in single-phase output mode, said system operates as multiphase converter by utilizing all the switches as shown in Figure 10 of the T-NPC inverter stage [300] and modifying output terminal connection corresponding to a single phase rated output load [900] and a single-phase utility grid connection [1000] in the output mode selector switch with filter stage [500]. The pulse width modulation signals generated at the pulse width modulation section [425] are phase shifted by 120º as shown in Figure 12 for each leg within a pulse width modulation period to utilize the switches of the inverter stage [300] ensuring full power delivery rating in both three phase and single-phase mode.

The voltage generation section [200] is eliminated for direct coupling as shown in Figure 4 if the input voltage is more than 570V and only three phase loads are to be powered or load voltage requirement is not stringent as in case of pumps. The control section [400] as shown in Figure 9 consists of a signal conditioning with error signal generation section [411], a MPPT controller [413], a digital voltage controller [415], an input DC source selection block [412], a mode control section [414], a DC-link capacitor voltage balance controller [416] and a Pulse width modulator [417]. The DC-link capacitor voltage balance controller [416] monitors the DC voltage balancing across the DC-link capacitors and appropriate control action is carried out. In an aspect, the DC-link split capacitors as shown in Figure 5 are directly used to generate three level DC voltage. The mode control section [414] controls the MPPT controller [413] and digital voltage controller [415] based on the input source [100] and topology used for the voltage generation section [200].

Using suitable algorithm, the digital controller [410] generates PWM for G1 and G2 in the voltage generation section [200]. The algorithm with required feedback maintains voltage balance across C1 and C2 as shown in Figure 2 apart from boosting the input voltage to achieve Maximum Power Point tracking (MPPT). Using sine wave modulation or space vector modulation or proprietary algorithm, the output mode selection control unit [420] generates the required PWMs for GA1, GA2, GA3, GA4, GB1, GB2, GB3, GB4, GC1, GC2, GC3 and GC4.

For simplicity GA1, GB1 and GC1 PWM signals are shown in Figure 12 which represents one half cycle of single-phase sine wave. Other 9 PWM signals follow the same rules as in 3 level T-Type Inverter. Section 426 as shown in Figure 11 is used to channelize the control pulses suitable for the inverter stage [300]. The changeover with line filter stage [500] provides higher flexibility for using the said three-phase three-level inverter system to modify the output section as per user need and unused system elements can be removed to make the system cost effective.

In another preferred embodiment, in case only three phase loads to be powered using input voltage with 570V or load voltage requirement is not stringent as in case of pumps, the three-level voltage generation section [200] is modified to a conventional 2-level booster scheme as shown in Figures 6 and 7.

In another preferred embodiment, if the DC input power source is a regulated source/battery or group of batteries and load power requirement is balanced 3-phase or low, direct coupling is used in the three-level voltage generation section [200] as shown in Figure 4 and 5. The capacitor voltage balance is achieved with advanced switching algorithm.

In another preferred embodiment of the present invention, the solar PV input source can also be used when load voltage restrictions are not strict by employing MPPT in the output mode selection control unit [420].

For low power rating applications with stringent voltage demanding loads, conventional boost converter with DC-link voltage split capacitors as shown in Figures 6 and 7 are used in the two-level voltage generation section [200]. In this type of topology MPPT is employed in the digital controller [410] in the control section [400] and output voltage is well regulated with closed loop control. The capacitor voltage balance is achieved with advanced switching algorithm.

In case of medium and high-power applications, unbalance in load will cause severe voltage unbalance in DC-link split capacitors leading to high THD at inverter output. High power application needs a capacitor voltage balancing digital controller and hardware. This is achieved with three-level booster topology. Voltage across C1 and C2 are monitored and regulated to desired value along with MPPT. Figure 3 depicts the three-level booster structure of the three-level voltage generation section [200]. Multiple solar panel strings with different powers and MPP characteristics can be combined allowing parallel connection of multiple booster modules.

The outputs at any time can be adopted for one of the below:
• High performance variable frequency rated induction/permanent magnet three phase motor/pump load.
• Traditional three phase loads including induction motor/permanent magnet motors.
• Three phase grid feeding.
• Full rated single-phase load.
• Full rated single-phase grid feeding.
• Or combination of the above requirements.

Thus, the three-phase three-level inverter system with interleaved single-phase output according to the present invention, achieves higher throughput using interleaved topology for single-phase load, dual or multiple booster with voltage balancing capacity for medium and high-power ratings. Also, the three-phase three-level inverter system with interleaved single-phase output according to the present invention provides low-harmonic, low spiky electrical power to traditional three-phase or single-phase motor loads used in agrarian applications and can be a single-phase or three-phase grid tied inverter as well.

The foregoing description comprises illustrative embodiments of the present invention. Having thus described exemplary embodiments of the present invention, it should be noted by those skilled in the art that the within disclosures are exemplary only, and that various other alternatives, adaptations, and modifications may be made within the scope of the present invention. Merely listing or numbering the steps of a method in a certain order does not constitute any limitation on the order of the steps of that method. Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions. Although specific terms may be employed herein, they are used only in generic and descriptive sense and not for purposes of limitation. Accordingly, the present invention is not limited to the specific embodiments illustrated herein.

,CLAIMS:WE CLAIM:
1. A three-phase three-level inverter system with interleaved single-phase output, said system comprising:
an input power source [100];
a three-level voltage generation section [200];
an inverter stage [300];
a changeover with line filter stage [500];
a control section [400] consists of a digital controller with MPPT [410] for the voltage generation section [200] and inverter control stage [300] with output mode selection control unit [420];
a wired or wireless module [430]; and
a portable device [440],
wherein the inverter stage [300] output is fed to the changeover with filter stage [500],
wherein the inverter stage [300] is made up of line frequency filters for harmonic content reduction and selection switches to modify the inverter output according to the load type selected,
wherein the changeover with filter stage [500] provides three phase or single phase power output to off grid loads and three phase or single phase on grid loads,
wherein the digital controller [410] based on system voltage, current and temperature feedback carries out hardware diagnostics and reports data to the portable device [440] via the wired or wireless module [430], and
wherein the configuration required for hardware is based on load requirement and rating is automatically set by the digital controller [410].

2. The system as claimed in claim 1, wherein the inverter stage [300] is a T-Type Neutral Point Clamped (T-NPC) inverter consisting of 12 switches used for DC-AC conversion.

3. The system as claimed in claim 1, wherein the changeover with line filter stage [500] comprises of contactor/relays which are controlled by a digital control block [423] of the output mode selection control unit [420] through control signals to K1 to K5 based on user input commands from the portable device [440] via the wired or wireless module [430].

4. The system as claimed in claim 1, wherein the three-level output voltage from the voltage generation section [200] is directly connected to the inverter stage [300] and appropriate gate control pulses are generated in the output mode selection control unit [420] to produce the output with desired voltage and frequency.

5. The system as claimed in claim 4, wherein the output mode selection control unit [420] consists of a signal conditioning and sensing section [421], a system operation mode selection processing sub section [422], a three phase or single-phase voltage and current controller section [424] used to generate control signals followed by a pulse width modulation section [425].

6. The system as claimed in claim 5, wherein the system operation mode selection processing sub section [422] is used for load type selection as per user requirement through the wired or wireless module [8].

7. The system as claimed in claim 3, wherein the digital control block [423] is used to appropriately select the operating modes of the three phase or single-phase voltage, current controller section [424] and the pulse width modulation section [425] as per input and generates control signal for the output mode selector switch with filter stage [500].

8. The system as claimed in claim 1, wherein in single-phase output mode, said system operates as multiphase converter by utilizing all the switches of the T-NPC inverter stage [300] and modifying output terminal connection corresponding to a single-phase rated output load [900] and a single-phase utility grid connection [1000] in the output mode selector switch with filter stage [500].

9. The system as claimed in claim 5, wherein pulse width modulation signals generated at the pulse width modulation section [425] are phase shifted by 120º for each leg within a pulse width modulation period to utilize the switches of the inverter stage [300] ensuring full power delivery rating in both three phase and single-phase mode.

10. The system as claimed in claim 1, wherein the voltage generation section [200] is eliminated for direct coupling if the input voltage is more than 570V or load voltage requirement is not stringent as in case of pumps and only three phase loads are to be powered.

11. The system as claimed in claim 1, wherein the control section [400] consists of a signal conditioning with error signal generation section [411], a MPPT controller [413], a digital voltage controller [415], an input DC source selection block [412], a mode control section [414], a DC-link capacitor voltage balance controller [416] and a pulse width modulator [417].

12. The system as claimed in claim 11, wherein the DC-link capacitor voltage balance controller [416] monitors the DC voltage balancing across the DC-link capacitors and appropriate control action is carried out.

13. The system as claimed in claim 11, wherein the mode control section [414] controls the MPPT controller [413] and digital voltage controller [415] based on the input source [100] and topology used for the voltage generation section [200].

14. The system as claimed in claim 1, wherein the input power source [100] includes a solar PV or a battery or a DC source.