FIELD OF INVENTION:
The present invention relates to a sine wave inverter/ uninterruptible power supply (UPS) and more particularly to a three phase sine wave inverter/ uninterruptible power supply (UPS) with bi- directional converter.
PRIOR ART:
Three phase bidirectional inverter/ UPS operate in conjunction with the existing electrical systems to provide power conditioning, back-up protection and distribution for electronic equipment loads that use three-phase power. It also prevents power disturbances such as outages, sags, surges, spikes and noise from affecting the performance and life of the electronic device and vital data. Common controller configuration loop inverter and rectifier circuits are utilized for bidirectional inverter. Various energy conversion configurations have been developed in order to allow such functions which are explained in US Patent No. 6160722, US Patent Publication No. 2004/0062059, US Patent No. 6587362, US Patent Publication No. 2003/0057919 and US Patent No. 6750685 which are hereby incorporated for reference. Furthermore, traditional energy conversion systems used as battery chargers are unable to adapt to various energy storage technologies, such that single customized designs are required for a given battery technology.
Therefore a need exists for three phase sine wave inverter/ UPS with bidirectional converter that enables bidirectional conversion between AC and DC within the same component or circuit.
US publication no. 20100244775 relates to a bidirectional converter that operates under an AC generation mode or a charge mode. The bidirectional converter may be a single component or circuit, which may include a DC-DC conversion stage using a unique "Smith 2 Stage conversion" technique and a DC-AC conversion stage or AC-DC conversion stage using a switchable filter depending on the mode. During the charge mode, the converter may be able to control the voltage and current of the DC output using a software algorithm, to match the battery being charged, or the DC receiver. This may enable the converter to control the nature of the DC output so it can be adapted to any energy storage technology. The controllable output voltage and synchronically frequency may allow the converter to be used in series combinations to achieve a variety of high voltage outputs from simpler building blocks.
US patent no. 7,141,892 relates to a power supply method of line interacting UPS. This system becomes complicated and costly for moderate and high power application like 1 KVA, 1.5KA and 2KVA. This system is not suitable for external battery (I/O) because there is no galvanic isolation of battery from the input and output AC power.
US patent no. 7,050,312 provides an uninterruptible power supply apparatus including two bidirectional power converter circuits having first and second ports. The apparatus further includes a DC link that couples the second port of the first bidirectional power converter circuit to the first port of the second bidirectional power converter circuit.

Publication no. CN2558136 discloses is a high-voltage uninterruptible power source, pertaining to the power supply technology. The circuit of the utility model is composed of a three-phase AC input transformer and a power unit module circuit. The power unit modules of each phase are connected with a three-phase output transformer and a controller with each charger respectively used; the controller is composed of a single-chip microcomputer circuit, an industrial control computer and a logic program controller connected with each other.
Publication no. JP2003134694 provides an interruptible power supply system which uses a bidirectional inverter connected with a transformer for detecting voltage in which an over current is prevented from flowing to the transformer when power is supplied to a load from a three-phase AC power supply. When the three-phase AC power supply is abnormal, power is supplied by the DC power supply. A switch is provided to a circuit connecting the virtual neutral point and the neutral point on the primary side of the transformer. The switch is turned OFF when power is supplied by the three-phase AC power supply and turned ON when power is supplied by the DC power supply.
US patent no. 5,563,778 is about an improved uninterruptible power supply system which includes a converter for converting alternating current voltage into a direct current voltage; an inverter for modulating the direct current voltage outputted from a battery or the converter; a first switch for switching the voltage modulated at the inverter; a second switch for switching the alternating voltage inputted via a bypass line and an integrated transformer for increasing or decreasing the output voltages of the first and the second switches. The transformer also acts as a reactor for shaping the output voltage of the first switch; and a condenser for shaping the waveforms of the output voltage of the integrated transformer.
US patent 5,602,725 discloses a special purpose custom power control apparatus outputs AC power having more particular characteristics relative to the AC power input thereto. Duty ratio of operation of GTO devices is controlled to transform the input power to the output power having its particular characteristics.
US publication no. 20080278005 discloses an uninterruptible power supply comprising two different power converters for converting AC voltage on the first input into DC voltage and DC voltage into AC voltage on the power supply output.
US patent no. 7,508,094 provides a power supply system having a multi-mode converter that may be coupled to a DC link of the UPS and configured to be selectively coupled to a battery and the AC input to respectively support battery conversion and current control at the AC input in respective first and second modes of operation of the UPS.
US patent no. 7,141,892 provides a power supply method and apparatus of a line interactive UPS utilizing a bi-directional AC/AC power converter in association with the AC delta control concept. When the line voltage coupled to the AC/AC power convert exceeds high/low statuses,

the UPS is operated in a line voltage conversion mode, wherein the AC/AC power converter supplies a voltage to compensate the line voltage based on the stability of the line voltage. Then the compensated stable voltage is further provided to the load so as to perform the voltage boost (step-up) and/or voltage buck (step-down).
US patent no. 7,088,601 provides a UPS which includes first and second DC voltage busses and a poly phase DC to AC converter circuit coupled to the first and second DC voltage busses and operative to generate a poly phase AC output. The poly phase DC to AC converter circuit includes respective half-bridge circuits that drive respective phases of the poly phase AC output. The control circuit is operative to provide discontinuous modulation of at least one of the half-bridge circuits. The apparatus may include an AC to DC converter circuit operative to generate a DC voltage between the first and second DC voltage busses from an AC input.
US patent no. 6,330,170 discloses a soft-switched single-phase quasi-single-stage (QSS) bi¬directional inverter/charger that converts AC-DC or DC-AC. The inverter/charger comprises a push-pull inverter/rectifier on the dc-side, an isolation transformer which provides ohmic isolation and voltage scaling, two full-bridges on the AC side in cascade, a voltage clamp branch comprising a capacitive energy storage element in series with an active switch with its anti-parallel diode, a passive filter at the ac side to smooth out the high frequency switching voltage ripple at the output, and a corresponding PWM scheme to seamlessly control the converter to operate in all four quadrant operation modes in the output voltage and output current plane, and is capable of converting power in both directions.
US Publication No. 20100277002 relates to a power conversion system includes a power converter, a transformer, and a voltage adjustment device. The power converter is configured to receive a variable DC power generated by a power generation device and to convert the received DC power to AC power at a first voltage.
(Above is a 2 stage configuration, receive variable DC power from the PV system and convert to AC power at the first voltage by using Power converter and then configured same AC power through transformer to a second AC voltage to grid system). This patent does not talk about semi boost rectifier topology and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters.
Publication No. JP2010187431 relates to an uninterruptible power supply which is suitable as an uninterruptible power supply that generates a three-phase AC voltage of three-phase/four-line system so as to supply a three-phase/four-line load with electricity while operating a plurality of units mutually concurrently. This patent does not talk about bidirectional inverter and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters. Same is for UPS.
Publication No. KR100964599 relates to uninterruptible power supply system and a device thereof are provided to maintain the equilibrium of three phase voltage by independently compensating each phase voltage of the three phase mode. This patent does not talk about

bidirectional inverter and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters. Same is for UPS.
US Publication No. 20100314944 relates to a power input and a power output that may be selectively configured to accommodate changes in the power requirements of an uninterruptible power supply. This patent does not talk about semi boost rectifier topology and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters. Same is for UPS and has no claim for bidirectional inverter.
US Publication No. 20110245990 relates to a system and a method for connecting and/or interfacing a converter, such as a switched mode converter, to an electrical power grid. This patent does not talk about semi boost rectifier topology and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters.
US Publication No. 20090244936 relates to a three-phase inverter with a circuit arrangement having a DC voltage input for at least one direct voltage source and a three-phase alternating voltage output for feeding into a three-phase alternating voltage mains. This patent does not talk about bidirectional inverter configuration with transformer isolation/ semi boost topology and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters.
US Publication No. 20100141035 relates to a solution for incompatibility between nonsinusoidal waveform uninterruptible power supply (UPS) systems and active power factor correction (PFC) loads. This patent does not talk about bidirectional inverter and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters. Same is for UPS.
US Publication No. CN101707388 relates to a fuel cell uninterrupted power supply device comprising a main circuit and a control system, wherein the main circuit comprises a by-pass switch, a three-phase four-wire rectifier, a three-phase four-wire inverter, a fuel cell, a direct current to direct current converter, a bidirectional direct current to direct current converter and a super capacitor stack. This patent does not talk about rectifier control with both 3 phase 3 wire input as well as 3 phase 4 wire input, having same control parameters like input PF at unity control, charging current, charging voltage. Also has no claim for auto calibration of sensing parameters.
US Publication No. KR20090089436 relates to current sensors for uninterruptible power supplies (UPS). A UPS has a current sensor for controlling operation of a UPS main power circuit positioned in series with the AC supply voltage so as to measure the net current used by each

component connected to the UPS main power circuit. Feedback from the current sensor received by a control circuit is used to achieve unity power factor operation with the UPS. The rectifier configuration has sensing current element in series with AC supply and has no claim for sensing current element in each phase IGBT level with semi boost topology for input PF at unity control and has no claim for auto calibration of sensing parameters.
US Patent No. 7,710,747 relates to an inverter apparatus that rectifies a three-phase AC voltage of an AC input power supply using a rectifying circuit, converts the rectified voltage into a three-phase AC voltage having predetermined frequency and amplitude, on the basis of an output voltage command signal, using an inverter circuit that is subjected to pulse width modulation control, and supplies the three-phase AC voltage to a load. This patent does not talk about sensing current element in each phase IGBT level with semi boost topology for input PF at unity control and static switch bypass regulated voltage to load mode and has no claim for auto calibration of sensing parameters.
Publication No. WO2008003033 relates to computer simulation techniques with real-time system monitoring and optimization of electrical system performance. This patent talks about on computer simulation technique and has no claim for semi boost rectifier topology and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters.
Publication No. JP2009278835 relates to a bidirectional converter which provides for general-purpose use rather than exclusive use and reduces man hours and cost related to development or the like as the whole power supply, and also to provide a generation method for the bidirectional converter. This patent does not talk about bidirectional inverter configuration with transformer isolation / semi boost fixed frequency control topology and auto calibration of sensing parameters.
Publication No. CN201435681 relates to a switch-switching type high-voltage inverter comprising a transformer with multiple secondary line windings, 3m+l power units and two switch groups; the 3m+l power units include a standby power unit, 3m power units are equally divided into three groups, and each group respectively comprises m power units connected in series to from a phase line of the inverter; an output terminal of the standby power unit is connected with the second phase line; the first and the third phase lines are respectively connected with the first and the second switch groups, and selectively communicated with a first contact or a second contact of the standby power unit under the control of the two switch groups. This patent talks about multiple secondary winding of transformer in inverter case and has no claim for auto calibration of sensing parameters. Over system with single secondary winding in bidirectional converter mode either on inverter or on rectifier and more relies on input and output PFC control.
Publication No. CN 201435680 relates to a high-voltage inverter having monolithic power unit redundancy and comprising a transformer with multiple secondary line windings, 3m+l power units and three switch groups; the 3m+l power units include a standby power unit, 3m power

units are equally divided into three groups, and each group respectively comprises m power units connected in series to from a phase line of the inverter; the first, the second and the third phase lines are communicated with the positive electrode or the negative electrode of the output terminal of the standby power unit respectively through the control selection of the first, the second and the third switch groups. This invention talks about multiple secondary winding of transformer in inverter case and has no claim for auto calibration of sensing parameters. Over system with single secondary winding in bidirectional converter mode either on inverter or on rectifier and more relies on input and output PFC control.
Publication No. JP2011120325 relates to a compact and low-cost power converter by effectively controlling voltage of a DC power supply of a single-phase inverter connected in series to an AC output line of a three-phase inverter. This patent talk about grid interactive 3 phase semi boost rectifier in bidirectional inverter configuration and static switch bypass regulated voltage to load mode and has no claim for auto calibration of sensing parameters.
Publication No. CN201319509 relates to a full digital control three-phase input and output power frequency online UPS power supply, which comprises rectified current with a power factor correction circuit inside which is connected with the input end of the commercial power, and the output end thereof is connected with the input end of an inverter circuit and both ends of anode/cathode of a battery. This patent does not talk about for bidirectional inverter and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters.
Publication No. KR100981792 relates to three phase power source UPS (Uninterruptible Power Supply) and a battery charge control method thereof are provided to improve the lifespan and stability of a battery by controlling the charge voltage and charge current of a battery through a DC-DC chopper part. This patent does not talk about bidirectional inverter and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters.
Publication No. KR100984323 relates to single phase-single phase online UPS device, a three phase-single phase online UPS device, and a battery charge control method thereof are provided to secure a normal operation regardless of the change of the number of batteries by controlling an inverter part according to the output voltage of a battery. This patent does not talk about bidirectional inverter and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters. Same is for UPS.
Publication No. JP2010041744 relates to an uninterruptible power supply device that uses hardware in common for use at a three-phase three-line alternate current and a three-phase four-line alternate current, and to provide a method of manufacturing the same. This patent does not talk about bidirectional inverter and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters. Same is for UPS.

Publication No. 20110227415 relates to an uninterruptible power supply for providing power to a load. The uninterruptible power supply includes an input to receive input power, an output to provide output power, a plurality of battery modules that provide backup power, a power circuit coupled to the input, coupled to the plurality of battery modules and coupled to the output to provide power derived from at least one of the input power and the backup power to the output, a controller, a return line coupled to the controller and coupled to each of the battery modules, and a first sense line coupled to the controller and coupled to the plurality of battery modules. This patent does not talk about bidirectional inverter'and static switch bypass regulated voltage to load mode and auto calibration of sensing parameters. Same is for UPS.
Publication No. 20100014335 relates to a three-phase power converting apparatus for connecting a distributed power generation source, such as a solar battery, to a three-phase power system. This patent does not talk about star-star power transformer in semi boost rectifier control topology and static switch bypass regulated voltage to load mode and has no claim for auto calibration of sensing parameters.
Reference may be made to an article by Koutroulis, E. Chatzakis, J. Kalaitzakis, K. Voulgaris, N.C. Dept of Electronics & Computer Engineering, Tech. Univ. of Crete, Chania, Jul 2001, Volume 148, Issue 4, 315 - 321. The article talks about a new method for the design of a bidirectional inverter based on the sinusoidal pulse-width modulation principle and the use of a low-cost and lightweight ferrite-core transformer is presented. The inverter is designed for either ohmic or inductive loads. In the case of inductive loads, the reactive power is transferred back to the DC input power source using a new active rectifier design. The inverter is controlled by two minimum-time feedback loops, providing relatively low output voltage distortion (less than 2% for DC input higher than 24 V) and good load regulation (better than 2%), while the inverter efficiency remains relatively constant (from 80 to 85%) over a wide output power range (75 to 200 W) and DC input voltage range (23 to 28 V). Theoretical results are experimentally verified using a laboratory prototype
Reference may be made to an article by Telecommunications Energy Special Conference, 1994. TELESCON '94. The first International,.page(s): 357 - 359,11-15 April 1994. According to this article, in the line-interactive concept, an optimal approach to UPS is proposed by Bouwknegt, K. in which an alternative topology is proposed, in which there is only one bidirectional power converter between AC power and storage means that is still capable to stabilize and filter the AC input power without the disadvantages like the complexity and losses of the dual conversion and to the relatively high harmonic content of the AC input current. UPS systems based on this "line-interactive" concept are now available as three phase units ranging from 2okVA as static UPS systems with battery to over 10 MVA as rotary systems with kinetic energy storage and an integrated diesel engine.
The prior system requires an extra rectifier or converter or transformer to charge the batteries. Hence a backup system is required in inverter/ UPS which eliminates the need of an extra

rectifier or converter or transformer to charge the batteries and can charge the battery/ battery bank even in unbalance phase voltage.
In order to overcome above listed prior art, the present invention provides a three phase three wire as well as three phase four wire input grid interactive rectifier control with input power factor correction and can continue operation based on user setting with any number (less than or equal to three) of available phases with negligible deviation in input Power Factor.
The present invention also provides three phase three wire as well as three phase four wire User Defined selection of Phases to load in Grid interactive bypass mode with Load synchronization, auto voltage regulation (AVR) and input Power Factor correction.
Further, the present invention provides three phase three wire as well as three phase four wire User Defined selection of Phases to load in Inverter mode with output voltage regulation and Harmonics elimination.
The system is having bidirectional configuration with power converter, a transformer, static switch, battery and controller. The system sensing parameters are user configured with auto calibration options. It eliminates the extra rectifier or converter or transformer required to charge the batteries. The invention improves the input power factor during battery charging (rectifier) and bypass mode (input Grid bypass to load operation parallel with rectifier operation), which reduces the input power requirements and electricity bills.
OBJECTS OF THE INVENTION
The main objective of the present invention is to provide a three phase sine wave inverter/ stand by UPS having a bidirectional converter to convert the DC power to AC power when mains is not available and convert AC power to DC power when mains is available.
Another object of the present invention is to convert the stored DC powers of batteries to sine modulated AC power by using 3-phase DC-AC converter and a switch to output load in case of failure/ bad quality of input grid power.
Another object of the present invention is to charge the external batteries of different capacities in mains mode by using same 3-phase converter being used for DC-AC conversion during back¬up mode.
Another objective of the present invention is to have provision of connecting or disconnecting the input neutral from input power section of the system.
Another objective of this invention is to provide an inverter/ uninterruptible power supply to the connected load through external batteries of selective capacities.
Yet another object of the present invention is to achieve very high efficiency in bypass mode of the system.

Yet another object of the present invention is to eliminate the extra rectifier or converter or transformer required to charge the batteries.
Still another object of the present invention is to improve the input power factor during battery charging by operating 3-phase converter in boost converter mode. This results in significant reduction in the input power requirements and electricity bills.
Still another object of the present invention is to charge the battery bank under unbalance phase voltages.
Another objective of the present invention is to efficiently utilize the features of programmable controller for producing PWMs to generate the sine wave output and to control the charger in various charging mode, doing complex operations and complete control and monitoring of the overall inverter/ UPS functionalities.
Another objective of the present invention is to have complete isolation of external batteries and input/output AC lines by using isolated input and output line sensing feedback and control circuitry. The battery terminals are completely isolated from the input and output AC power and hence it is completely safe.
Another object of the present invention is to provide a synchronized change over with transfer time suitable for all kinds of equipments from mains mode to backup (inverter) mode and vice-versa.
Another objective of the present invention is to provide an automatic startup of the inverter/ UPS in mains mode to charge the batteries when output is disabled and line input supply resumed or made available.
Another objective of the present invention is to provide local or remote communication monitoring, setting and data logging of various system parameters for the required operation and analysis of the system performance and power quality etc.
It is, therefore, the overall object of the present invention to provide an uninterruptible power supply which overcomes the drawbacks and disadvantages of uninterruptible power supplies known in the prior art.
SUMMARY OF THE INVENTION
Accordingly, the three phase sine wave inverter/ uninterruptible power supply (UPS) with bidirectional converter comprises of 3-phase power converter, a transformer, static switches, battery/battery bank, controller, AVR transformer connected at input mains etc. 3-phase converter works as a DC to AC converter to transform the battery power (DC source) into AC sine wave power when grid power fails or becomes out of specified range with output control. When grid power available in a healthy condition, the same 3-phase converter works in boost mode for AC to DC conversion to charge the external or internal inverter batteries/battery bank in mains mode having improved input power factor control and charger operation can take place

with any number (less then or equal to three) of available phases with neutral or without neutral and even in single phase with neutral. The bypass mode parallel with charger operation also takes place line interactive User configurable selection of Phases to Load with synchronization and input power Factor improvement.
The present three phase sine wave inverter/ uninterruptible power supply (UPS) with bidirectional converter can be configured to a three phase three wire as well as three phase four wire input Grid interactive rectifier control having charging control with three phase, two phase (with or without neutral) and single phase with neutral Grid input with input power factor correction and three phase three wire as well as three phase four wire output control having User configurable setting for three phase, two phase (with or without neutral) or single phase with neutral output to Load without any deviation in specified controlled parameters like voltage regulation and harmonics eliminations.
The system sensing parameters are user configured with auto calibration options.
In an embodiment, the tapings of AVR transformer are selected in such a way that during the AVR mode, inverter bypasses healthy grid power directly to the load without any boost/buck operation of the mains supply by synchronizing input mains to load through static switch configuration.
In an embodiment, the same static switch configuration works in inverter operation (DC to AC) also acts as a parallel control for User defined selection of phases to Load i.e. three phase or two phase (with or without neutral) and single phase with neutral to load without any deviation in Load controlled parameters.
In another embodiment, the present system with bidirectional converter is used as a DC-AC converter to run the load in a backup mode and as an AC-DC converter to charge the external or internal battery bank during the mains mode and three phase AVR taped transformer with static switch for bypass operation.
In another embodiment, the present invention provides a user interface for configuring the system as per requirement such as but not limited to the setting of battery low cut, boost and float voltage, charging current setting, input mains voltage and frequency window for AVR and charger operation, output voltage setting and events logging like number of events of mains failures, mains low/high, frequency limits outage, overload, short circuit, battery low, User defined selection of phases to Load in bypass and inverter operation or in both etc.
The present invention provides the local and remote communication and display and key interface monitoring, setting of system parameters and auto calibration of sensing parameters.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS;
Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings and wherein:

Figure 1 shows a block diagram of three phase sine wave bidirectional converter according to the present invention;
Figure 2A, B, C, D shows a flow chart according to the present invention;
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
The present invention discloses a sine wave inverter/uninterruptible power supply (UPS) with bidirectional converter.
Reference may be made to figure 1 which shows a block diagram of three phase sine wave inverter/ uninterruptible power supply (UPS) with bidirectional converter which can be configured to a three phase three wire as well as three phase four wire input grid interactive rectifier control with input power factor correction and three phase three wire as well as three phase four wire output control with voltage regulation, Harmonics elimination. The system comprises 3-phase converter. 3-phase converter works as a DC to AC converter to transform the battery power (DC source) into AC sine wave power when grid power fails or becomes out of specified range. The system is User configured for selection of Phases to Load in inverter operation as well as in bypass operation and during the bypass operation, charger (rectifier) works without any deviation with user selected phases.
The system sensing parameters are user configured with auto calibration options.
The present invention charges the external batteries of different capacities in mains mode by using same 3-phase converter three IGBT control in boost mode without any inductor choke in the charging path being used for DC-AC conversion during back-up mode. As transformer winding acts as inductor for boost operation and ripple filter out. There is a provision of connecting or disconnecting the output neutral from output power section of the system. The system is an inverter with negligible interrupted power supply to the connected load through external batteries of selective capacities. The system provides very high efficiency, voltage regulation using AVR tapings of transformer with static switch at input mains in bypass mode of the system and synchronous input power to load transfer by using static switch in bypass operation with input Power Factor correction. The system provides 3 phase mains line interaction in three phase, two phase (with or without neutral) and single phase with neutral for charging operation with Power Factor correction. The system provides inverter output in three phase, two phase (with or without neutral) and single phase with neutral as per User configuration through Static switch control with output voltage regulation and harmonics elimination.
In the inverter stage power transfer follow the loop as Battery voltage (1) to Power converter PWM control (Q1, Q2, Q3, Q4, Q5, Q6) (2) to 3 phase isolated transformer (3) to Static switch (D11, D12, D21, D22, D31, D32) (4) act as a control and configurable source for User defined selection of phases to Load (5).

As the start step in the inverter operation Fig 2 (A-D), take calibration constant of battery voltage, battery current, output three phase voltages(R01, R02, R03, R04) and output three phase currents (IR, IY, IB, IN) from the settable calibration parameters last saved in the ROM during auto calibration. Set modulation index for PWM control power converter IGBT (Q1, Q2, Q3, Q4, Q5, Q6) (2) in reference of comparison Battery Voltage and Reference Sine wave (Computational Block I) to get pre defined nominal voltage to the static switch (4). Controller (7) controls static switch (4) operation to synchronize the voltage to the undefined load as per User defined selection of phases to Load (Computational Block E) through firing control of (D11, D12, D21, D22, D31, D32) (4).
Operation of the inverter now will get continuously control in reference to output three phase voltages (RO1, RO2, RO3, RO4) and output three phase currents (IR, IY, IB, IN) through feedback and feed forward control loop (Computational Block H) through PWM driver operation to IGBT (Q1, Q2, Q3, Q4, Q5, Q6) (2). As in the parallel task input battery voltage and discharging current is also monitored (Computational Block I) to predict the battery health in comparison to the current output load (IR, IY, IB, IN) to adjust the modulation index for the PWM generation (Ql, Q2, Q3, Q4, Q5, Q6) to the power converter (2) by controller (7). The output 3 phase voltage (ROl, R02, R03, R04) and output 3 phase current (IR, IY, IB, IN) sensing is operated (Computational Block H) in fast sensing loop at every switching step to control the output unbalance load condition to achieve the voltage regulation and harmonics elimination in conjunction with slow sensing loop (Computational Block I) of Battery Voltage BATV and Battery current BATI (Computational Block F). The output neutral (Jl) (4) connection or disconnection is user configurable and only operates in three phase, two phase load connection controlled by controller (7) (Computational Block G) without any controlled Parameters deviations. During the operation controller (7) also take control of external PC monitoring (8), display user interface parameters on LCD (9), update LED status and sense user interface through switch (10). In parallel to above operations fast control of over current at the output load act as a short circuit current control or shut down stage decision as per the specified User defined parameters and slow control of battery voltage and battery discharging current act as system nominal modulation or over modulation control operation.
When grid power available in healthy condition, same 3-phase converter works in fly-back boost mode for AC to DC conversion to charge the Inverter external or internal batteries in mains mode known as rectifier control. The charging current and charging boost/ absorption/ float voltages are controlled by the PWM switching of three IGBT (Q4, Q5, Q6) (2) under the command of controller (7). Hence, the cost and size of the proposed system is reduced significantly with improved system efficiency.
In the rectifier stage, the power flow follows the same hardware configuration as in inverter, but in reverse (Fly Back) flow of direction. The power flow follows the loop as Mains input (RS1, RS2, RS3, RS4) (6) to auto voltage regulator (AVR) transformer tapings (6) to static switch transfer (D11, D12, D21, D22, D31, D32) (4) to Load ROl, R02, R03, R04 (5) and Mains input (RS1, RS2, RS3, RS4) (6) to 3 phase Transformer (3) to Power converter (Q4, Q5, Q6) (2) to battery parallel to filter capacitor (1).

As the start step in the rectifier operation Fig 2 (A-D), the same control loop exist for the inverter control configured for rectifier control, only the sensing parameters changed and controller (7) controls battery charging through only three IGBT (Q4, Q5, Q6) of power converter (2) (Computational Block B). Static Switch (Dl 1, D12, D21, D22, D31, D32) (4) with AVR taping of transformer connected at input Mains (6) acts for load bypass operation and as same used to claim a high rated system in lowest possible cost and low possible control loops. The rectifier operation operates on three phase or two phase or single phase input Mains Phases (RS1, RS2, RS3, RS4) (5), which seams to be healthy by controller (7). The input Mains Phases (RS1, RS2, RS3, RS4) (5) can be three phase, two phase (with or without neutral) or single phase with neutral, selected by Static switch (4) operation (Computational Block D) for bypass operation depend on the desired load configured by the User. Take calibration constant of battery voltage, battery current, input three phase voltages (RS1, RS2, RS3, RS4), input to transformer (3) three phase voltage (RI1, RI2, RI3, RI4) and input three phase currents (IL1, IL2, IL3) from the settable calibration parameters last saved in ROM of the controller (7) during Auto calibration.
Controller (7) sets the modulation index for PWM control power converter IGBT (Q4, Q5, Q6)
(2) in reference of nominal Half sine wave comparison with input three phase voltage (RI1, RI2,
RI3, RI4) (Computational Block C) as control loop follows the soft start constant voltage and
constant current battery charging. Further controller (7) compares the Battery Voltage (BATV)
(1) and Battery Current (BATI) (1) (Computational Block A) to control the charging operation in
conjunction with input three phase voltage (RI1, RI2, RI3, RI4) and input three phase currents
(IL1, IL2, IL3) to get control of input power Factor improvement without deviation in charging
operation through control of power converter IGBT (Q4, Q5, Q6) (2) (Computational Block B).
Controller (7) controls static switch (4) taped with AVR transformer (6) operation for synchronization, voltage regulation and input Power Factor improvement to the undefined load through firing control of (D11, D12, D21, D22, D31, D32) (4) by comparison of input Mains voltages (RS1, RS2, RS3, RS4) (6) and output voltages (RO1, RO2, RO3, RO4) (3) (Computational Block D). The Mains voltages (RS1, RS2, RS3, RS4) (6) connect to feed power for battery charging at transformer input (R11, R12, R13, R14) (3). The neutral of Mains input RI4
(3) connection or disconnection is User configurable and controller (7) controls the switch (JI)
(4) for the same (Computational Block G).
Operation of the rectifier now continuously controls in reference of battery voltage and battery charging current. In the parallel operation from the sensing of input current (IL1, IL2, IL3) (2) controller sensed the unbalanced condition of each phase input and in reference of same, duty cycle of PWM (Q4, Q5, Q6) (2) vary to correct the input power factor at unbalance input (RI1, RI2, RI3, RI4) (3) condition (Computational Block C). The same control loop runs with input neutral (RS4 - RI4) (4) connect as well as input neutral disconnect without any deviation in improvement of input power factor in both case. The prescribed rectifier control is operated through the PWM control to low end three IGBT (Q4, Q5, and Q6) (2) and above IGBT (Ql, Q2, Q3) at power stage (2) is permanently low, act as a freewheeling diode operation.

In the above operation fast control of input current (IL1, IL2, IL3) (2) comparison to input voltage (RI1, RI2, RI3, RI4) (3) (Computational Block C) actively correct the input power factor at every PWM switching stage. In parallel the feedback and feed forward control of constant current and constant voltage charging of battery actively control the ripple free charging of battery at every predefined time.
During the operation, controller (7) also takes control of external PC monitoring (8), display user interface parameters on LCD (9), update LED status and sense user interface through switch (10). In parallel to above operations fast sense of over current at the output load (IR, IY, IB, IN) (5) for output short circuit condition sensed by the controller (7) to control or Shut down Static Switch (4) stage decision as per the specified parameters and Mains (RSI, RS2, RS3, RS4) (6) high and low rectifier cut as mentioned in settable parameter in ROM defined by User through LCD (9) and remote configuration through PC (8).
As in the overall operation of the system, the User can configure system through user interface (10), display (9) as well as through PC (8) to recalibrate the system constant, by configure the system inverter and rectifier operation runs in default mode as per last load condition for short period as shown in figure 2A-2D.
Logical and analog circuitry, required for sensing of various parameters and generation of sine wave output is eliminated by low cost controller with inbuilt A/D converter to reduce the cost and complexity of the system. The present system with bidirectional converter is used as a DC-AC converter to run the load in a backup mode and as an AC-DC converter to charge the external or internal battery bank during the mains mode. The input power factor during battery charging is improved by operating 3-phase converter in boost converter mode. This results in significant reduction in the input power requirements and electricity bills. The battery bank can be charged even under unbalance phase voltages and with healthy available any number (less then or equal to three) of input phases.
The invention provides a three phase sine wave inverter in which AC line power is used to charge the battery and to operate a load during the mains available through AVR transformer taped(6) static switch (5) synchronizing mode of the inverter/ UPS and with controlled input Power Factor correction. The input can be connected or disconnected the from input power section of the system through switch J1 (4).
The invention provide a AVR transformer tapings with Static Switch conjunction with the system for bypass load synchronization, voltage regulation and input Power Factor correction operation and static switch alone in inverter operation to provide the desired phases at output Load configured by the User i.e. it can be configured that the output will be three phase, two phase (with or without neutral) and can be single phase with neutral.
The three phase sine wave inverter has communication with the PC for monitoring, setting and data logging of various system parameters for the required operation and analysis of the system performance and power quality etc and also configured through LCD interface through User

defined key at the front panel with all specified parameters. Auto calibration can take place through remote monitoring as well as through LCD user interface.
The present invention also provides a user interface for configuring the system as per requirement such as but not limited to the setting of battery low cut, boost and float voltage, charging current setting, input mains voltage and frequency window for AVR and charger operation, output voltage setting and events logging like number of events of mains failures, mains low/high, frequency limits outage, overload, short circuit, battery low etc..
It improves the input power factor in three phase three wire as well as three phase four wire input mains and with any number (less then or equal to three) of input healthy phase available during battery charging by operating three phase converter in boost converter mode. This results in significant reduction in the input power requirements and electricity bills.
Thus efficiently utilizes the features of programmable controller for producing PWMs to generate the sine wave output and to control the charger in various charging mode, doing complex operations and complete control and monitoring of the overall inverter functionality having user configurable auto calibration of sensing parameters. It also provides a synchronized change over with transfer time suitable for all kinds of equipments from mains mode to backup (inverter) mode and vice-versa by using static switch transfer configuration.
There is also provided auto calibration of sensing parameters by local and remote communication and by display and key interface user setting. User is able to configure battery rating through local and remote communication or through local LCD display and user interface. This invention provides a bidirectional inverter power supply configured for three phase three wire as well as three phase four wire system with a single control loop without any user setting.
This system is high rating system in the low possible cost by control the entire operation through single controller control loops and flow of operation through single hardware configuration.
It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-

WE CLAIM
1. A three phase sine wave inverter/ uninterruptible power supply (UPS) with bidirectional converter comprises a three phase three wire input or three phase four wire input or two phase two wire input or two phase three wire input or single phase two wire input Grid interactive rectifier (Battery charger) control with input power factor correction parallel with AVR transformer taped bypass Static Switch and User selection of regulated phases to Load transfer operation.
2. A three phase sine wave inverter/ uninterruptible power supply (UPS) with bidirectional converter as claimed in claim 1, may be configured to a three phase three wire output or three phase four wire output or two phase two wire output or two phase three wire output or single phase two wire output Load interactive (User configured) inverter with output voltage regulation, Harmonic elimination.
3. A three phase sine wave inverter/ uninterruptible power supply (UPS) as claimed in claim 1 or 2, comprises main input, static switch, AVR transformer with defined tapings, PWM control power converter, power transformer, battery bank, controller, sensing units, user interface, display, system interface wherein said controller controls AVR transformer taped static switch operation to synchronized voltage to the undefined load with input power factor correction and voltage regulation through firing control of static switch and also said controller controls static switch alone (without taped with AVR transformer) operation in inverter mode to provide User defined selection of phases to load and the PWM modulation index controls at least three switches (IGBT) of power converter during charging operation and the switches (IGBT) during inverter operation synchronized with static switch control to feed user defined type of Load.
4. The three phase sine wave inverter/ uninterruptible power supply (UPS) with bidirectional converter, as claimed in any of the preceding claims, wherein said three phase converter works in fly-back boost mode for AC to DC conversion to charge the Inverter external or internal Batteries in Mains mode wherein the charging current and charging boost/ absorption/ float voltages are controlled by the PWM switching under the logic of controller with input Power Factor correction on any number (less then three) of healthy phases available at input with or without neutral.
5. The three phase sine wave inverter/ uninterruptible power supply (UPS) with bidirectional converter, as claimed in any of the preceding claims, wherein said system sensing parameters are user configured with auto calibration such as herein described
6. The three phase sine wave inverter/ uninterruptible power supply (UPS) with bidirectional converter, as claimed in any of the preceding claims, wherein said system charges the external batteries of different capacities in mains mode by using same three-phase converter three IGBT control in boost mode without any inductor choke in the charging path for DC-AC conversion during back-up mode.

7. The three phase sine wave inverter/ uninterruptible power supply (UPS) with bidirectional converter, as claimed in any of the preceding claims, wherein the output neutral can be connected or disconnected from output power section of the system, which is User configured for three phase three wire output or three phase four wire output or two phase two wire output or two phase three wire output or single phase two wire output Load interactive through Static switch control.
8. The three phase sine wave inverter/ uninterruptible power supply (UPS) with bidirectional converter, as claimed in any of the preceding claims, wherein said inverter provides very high efficiency, voltage regulation in bypass mode of the system and synchronous input power to output power to load transfer with input Power Factor correction by using AVR transformer taped static switch in bypass operation, wherein the same is user configured for number of phases with or without neutral User defined selection of phases required at the output Load.
9. The three phase sine wave inverter/ uninterruptible power supply (UPS) with bidirectional converter, as claimed in any of the preceding claims, wherein said inverter provides synchronized, input and regulated output Power Factor corrected change over with transfer time suitable for all kinds of equipments from mains mode to backup mode and vice-versa by using static switch transfer configuration.
10. The three phase sine wave inverter/ uninterruptible power supply (UPS) with bidirectional converter, as claimed in any of the preceding claims, wherein said inverter improves the input power factor in three phase three wire input or three phase four wire input or two phase two wire input or two phase three wire input or single phase two wire input mains during battery charging by operating three phase converter in boost converter mode which reduces the input power requirements.