Photovoltaic Simplified Boost Z Source Inverter for Ac Module Applications

This study mainly proposed PV z source boost inverter used to boundary grid or ac module applications. Separate types of converter used for solar system due to its current lagging, here capacitor multiplier based boost converter introduced for maintain the current lagging and voltage gain. Here, the switched inductor z source inverter implemented for grid interface. Proposed z source inverter is controlled by pulse width modulation. A simplified capacitor multiplier controlled by continuous conduction mode, A detailed topology analysis and a generalized discussion are given. The multiplier boost converter has the merits of maintain voltage level and reducing cost and current lagging. Simulation results are implemented and analysis MATLAB software.


INTRODUCTION
The world's Renewable sources growing up recently and Photovoltaic (PV) market will grow up to 30 GW by 2014, due to the following policy-driven scenario (Xue et al., 2004).The role of grid-connected PV systems in distribution energy systems will become important and the PV inverter will also play a unique role in this growing market.To obtain higher dc-link a String-type inverters use series connections with numerous modules to the main electricity through a dcac inverter (Shimizu et al., 2006;Li and Hi, 2011).
Figure 1 shows that the Single-Ended Primary Inductance Converter (SEPIC) having non-inverting output voltage (Adar et al., 1997;Chiang et al., 2009).Although the boost converter usually has higher efficiency than the SEPIC, nonetheless, it is only applicable for cases where the battery voltage is higher than the PV module voltage (Kim et al., 2010).The SEPIC's buck boost features extends the applicable PV voltage and thus increases the adopted PV module flexibility.
The comparison of various buck-boost converters from voltage gain and efficiency and cost.It is shown in Table 1.Among these converters, although the SEPIC is not the best from the views of efficiency and cost, it still has the merits of no inverting polarity, user free-to-drive switch and low input-current expand for high-accuracy Maximum power point tracking that makes its integral point suitable for the low-power PV charger method.This study will investigate the SEPIC with the PV module input and zeta converter with PV module input.Switched z source inverter interface with SEPIC and Zeta converters.Zeta converter provides either a step-up or a stepdown function to the output, in a manner similar to that of the buck-boost or SEPIC converter topologies.The conventional Zeta converter is configured of two inductors, a series capacitor and a diode.Previous research work developed diverse Zeta converter applications, as follows.A coupled inductor can be employed to reduce power supply dimensions (Falin, 2010).
The features of the proposed zeta converter replaced inductor to the leakage-inductor.Leakage inductor energy of the coupled inductor can be recycled, increasing the efficiency and the voltage spike on the active switch has been restrained.The switchedcapacitor and coupled-capacitor techniques are introduced for high boost conversion range.During non operating condition active switch isolates the PV panel's energy to humans or facilities (Chen et al., 2013).
In Conventional System Inverters (VSI and CSI) (Yang and Smedley, 2008;Kerekes et al., 2009) are widely required in various industrial applications such as Induction drives, distributed power systems and hybrid electric vehicles.However, the normal VSI and CSI have been seriously restricted due to their stabilized output voltage range, shoot-through problems caused by misgating and some other theoretical difficulties due to their bridge-type structures.
The topology of the Z-source inverter (Peng, 2002) was used to limits the problems in the traditional  inverters (Yang and Smedley, 2008;2009).In which the functions of the traditional boost converter and the bridge-type inverter have been successfully combined.As a research troublespot in power electronics the Z-source.

PROPOSED CONVERTER METHO
Even though SEPIC converter having some merits, the proposed converter is shown in Fig. 3; its basic configuration came from a Zeta converter, but the input inductor has been replaced by a coupled inductor.Employing the turn's ratio of the coupled inductor increases the voltage gain and the secondary winding of the coupled inductor series with a switched capacitor for further increasing the voltage.The coupled Zeta converter is configured from a coupled inductor with the floating active switch ˟ # .The primary winding ˚# of a similar inductor ˠ # is similar to the input inductor of the existing boost converter, except that capacitor ˕ # and diode ˖ # are recycling leakage inductor energy from ˚#.The secondary winding connected with another pair of capacitors diode ˖ $ , all three of which are in series with rectifier diode ˖ % connects to its output capacitor and load R. The features of the proposed converter are

PROPOSED CONVERTER METHOD
Even though SEPIC converter having some merits, in Fig. 3; its basic guration came from a Zeta converter, but the input inductor has been replaced by a coupled inductor.Employing the turn's ratio of the coupled inductor increases the voltage gain and the secondary winding of eries with a switched capacitor for further increasing the voltage.The coupled-inductor gured from a coupled inductor ˠ # .The primary winding is similar to the input inductor of the existing boost converter, except that are recycling leakage-.The secondary winding ˚$ is connected with another pair of capacitors ˕ $ and with of which are in series with ˚#.The connects to its output capacitor ˕ % and load R. The features of the proposed converter are: inductor energy of the coupled inductor can be recycled, increasing the efficiency; voltage spike on the active switch has been conversion ratio is efficiently capacitor and coupledoating active switch isolates the PV panel's operating conditions, thus preventing any potential electric hazard to humans or facilities.The operating principles and steadystate analysis are presented in the following Proposed system suitable simplified boost range of capacitor Interface of grid we used switched z source inverter, proposed synchronized PWM topology used to produce high voltage gain in dc link side than conventional inverter (Zhu et al., 2010) been greatly explored from various aspects ( 2004).

Switched Z source network:
To provide a output power in inverter is a challeging issue and also z source converter performance is improved by addition of capacitor and inductor bank recently Purely based on high step up without non circuit, Switched z source is a suitable m module or grid interface even though if we have low DC source in our primary side.To provide a stabilized output power in inverter is a challeging issue and also z source converter performance is improved by addition of capacitor and inductor bank recently.
Purely based on high step up without non-isolation circuit, Switched z source is a suitable medium for AC module or grid interface even though if we have low An newest dc-dc conversion enhancement techniques such as Switched Capacitor (SC), Switched inductor (SL), hybrid SC/SL, voltage multiplier cells and voltage lift techniques have been greatly explored (Ioinovici, 2001;Zhu and Luo, 2009).
In this, the concept of the SL techniques has been integrated into the classical Z-source impedance network.Additionally three diodes, the introduced topology is termed the SL Z-source inverter and is shown in Fig. 5.This topology is totally different from any other existing Z-source inverters based on structure and operation principles.The main features are sum up in the following: • Low range of inductors and capacitors • Simplified and synchronized PWM topology for z source inverter • Additional boost factor over normal Z source inverter circuit with less duty cycle:

OPERATING PRINCIPLES OF THE PROPOSED CONVERTERS
The Simplified circuit model of the proposed (Chen et al., 2013) converter is shown in Fig. 3.The coupled inductor T1 includes a magnetizing inductor Lm, both leakage inductors H # and H $ and an ideal transformer primary winding ˚# and secondary winding ˚$.To simplify the circuit analysis of the proposed converter, the following assumptions are made: • All components are important, except for the leakage inductance of coupled inductor ˠ # .The ON-state resistance RDS (ON) all parasitic capacitances of the main switch ˟ # are neglected, as are the forward voltage drops of the diodes ˖ # ∼˖ % .• The capacitors ˕ # ~˕% are sufficiently large that the voltages across them are considered to be constant.• The ESR of capacitors ˕ # ∼˕ % and the parasitic resistance of coupled-inductor ˠ # are neglected.• The turn's ratio n of the coupled inductor ˠ # winding is equal to ˚$/˚#.
The operating principles for Continuous-Conduction Mode (CCM) are now presented in detail.The typical waveform of several major components during one switching period.The five operating modes are described as follows.

Modes of operations:
Mode I (Y , Y ): During these modes, energy transferred from the secondary leakage inductor L k2 to capacitor C 2 .switch S 1 and diodes D 2 are conducting.The current i Lm is descending because source voltage V in is applied on magnetizing inductor L m and primary leakage inductor L k1 ; same time, L m is also releasing its energy to the secondary winding, as well as charging capacitor C 2 along with the decrease in energy, no conduction from V in to load (Kerekes et al., 2009): Mode II (Y , Y ): During this modes interval J # and ˢ , ˖ % is conducted.Primary and secondary inductor I Lm and I lk1 gets energized charging and discharging of C 1 , ˕ $ and ˕ % .From ˕ % to Load flow is taken: Mode III (Y , Y ): During this transition interval, secondary leakage inductor H $ keeps charging ˕ % when switch ˟ # is off.˖ # ˖ % is conducting alone.IH # stored energy transferred through ˖ # ˕ # , ˕ $ gets charging.Through ˖ % ˕ % charging and discharge from it to load: Simple boost PWM topology of proposed Z source inverter: The switching pulse generation, peak value of three phase reference with modulation index compared with high frequency triangular signal (ˢ >ˢ is ON) and (ˢ <ˢ is OFF).
Voltage gain derived by: n Where inverter voltage Gain (G) derived by Boost factor (B) and Modulation index (M): Voltage stress across inverter device is derived by: .Extra gain over zeta is shown in Fig. 11.

RESULTS AND DISCUSSION
The Proposed topology simplified boost Z source inverter provided additional Power gain by presented Zeta converter.Maximum power Generation of

CONCLUSION
Proposed ZETA converter achieved a systematic Maximum PV power generation and efficient power flow.Simplified Boost Z source inverter provided satisfactory solutions for AC grid interface using simple Boost PWM topology.Simplified Boost z source inverter drawn a lossless PV power generations to grid.Result has been implemented in MATLAB (SIMULINK).

Fig. 3 :
Fig. 3: Proposed zeta converter Fig. 2 shows that block diagram of PV simplified boost z source inverter.

Fig. 2
Fig. 2 shows that block diagram of PV simplified boost

Fig. 4 :
Fig. 4: Key wave form voltage multiplier boost converter and suitable for PV generation (Chen waveform of voltage multiplier boost converter shown in Fig. 4.Interface of grid we used switched z source inverter, proposed synchronized PWM topology used to produce high voltage gain in dc link side than conventional inverter(Zhu et al., 2010) been greatly explored from various aspects (2004).

Fig. 4 :
Fig. 4: Key wave form voltage multiplier boost converterand suitable for PV generation(Chen et al., 2013).Key waveform of voltage multiplier boost converter shown Interface of grid we used switched z source roposed synchronized PWM topology used to produce high voltage gain in dc link side than ., 2010) topology has been greatly explored from various aspects(Peng et al.,

Fig. 11 :
Fig. 11: Load voltage and load current for M = 0.8 (L = 20 mH, C = 150 uF) Photovoltaic obtained by zeta.Proposed simple PWM topology carried out from the range of M = 0.2-0.8.Maximum Load gain obtained M = 0.8 in proposed circuit topology.

Table 1 :
Parameters of simulation and ˕ $ .Only diodes ˖ # and ˖ $ are conducting.IH # and I˖ # current decreases based on leakage energy still flows through ˖ # and continue charging capacitor ˕ # .H is delivering its energy through ˠ # and ˖ $ to charge capacitor ˕ $ .The energy stored in capacitors ˕ % is constantly discharged to the load R: