Proportional Resonant controller based Inter Leaved Boost Converter fed Unified Power Quality Conditioner System

UPQC is an useful FACTS controller between sending end and receiving end for improvement of voltage quality. This work deals with identification of suitable controller for closed loop operation of ILBC based UPQC. The Analysis and comparison of responses with PI, FOPID & PR are presented in this article. The results of PI based ILBC-UPQC systems are compared with those of FOPID& PR controlled ILBC-UPQC system. The objective of this work is to improve the time domain response of ILBC-UPQC using suitable controller. The ILBC is proposed for UPQC since it gives better performance than HSUC and TIBC. The comparison is done in terms of rise time, peak time, settling time & steady state error. The MATLAB results indicate superior performance with PR based ILBCUPQC system.

In perspective of the control technique being used for voltage rundown or swell compensations, the UPQC structures can be appointed UPQC-P, UPQC-Q, and UPQC-S [2]. The UPQC-P is thought to be a consistent UPQC, where voltage fall and swell pay are performed by implanting/holding the dynamic influence (in eliminate or of stage voltage) through the course of action some portion of the UPQC while the shunt inverter supports the load responsive influence, dynamic influence required by the plan inverter, and the adversities in the structure. For a comparative estimation of voltage hang and swell compensation, the VA loadings of course of action and shunt inverters will be most outrageous in the midst of the UPQC-P, compensating for the best voltage list. Thus, UPQC-P should be sketched out in light of the best, voltage hang compensation. While in case of UPQC-Q the voltage imbued through a game plan transformer is in quadrature with the source current. As needs be, plan inverter does not require any unique influence for reimbursing the voltage hang except for the trading and filtering setbacks. The UPQC-Q approach is obliged to voltage list compensation since it can't compensate for the voltage swell [2], [4]. For a comparable measure of rundown pay, UPQC-Q requires greater course of action imbuement voltage degree appeared differently in relation to UPQC-P [2]- [4], [7], [8]. This assembles the VA rating of the plan transformer basically.
Generally, the voltage sags and swells are brief term PQ issues. In this way, in UPQC-P and UPQC_Q, course of action inverter VA stacking might be utilized for brief terms. On the other hand, the shunt inverter VA rating is totally utilized watchful out the operation, as a result of steady load open power support and current consonant pay. To enhance the utilization of course of action some bit of UPQC in the midst of persisting state, some bit of load open power is reinforced by the game plan inverter in UPQC -S [5], {6]. This piece of course of action inverter improves its utilization, and in addition reduces the shunt inverter VA stacking. As a result of the stack responsive power sharing component of the game plan part, the rating of the shunt inverter in UPQC-S may be not as much as that in the UPQC-P. In any case, this is to the burden of a fairly extended course of action transformer rating and diminishment in the rate of swell pay limit.

B. Research Gap
The Literature [1]- [12] does not deal with PR controlled ILBC-UPQC system. This work proposes ILBC to reduce current ripple. The Literature does not deal with PR to improve time response of closed loop controlled ILBC-UPQC system. The PR is proposed since it improves stability and reduces chaotics in output.

II.
SYSTEM CONFIGURATION The block diagram of proposed system is shown in Figure -2. The capacitor of UPQC is charged by the Output of ILBC. The output voltage of PV is boosted using ILBC.The Battery is replaced by a PV system & ILBC to produce the voltage required to charge the capacitor. ILBC is preferred to single boost converter due to reduced input current ripple. Load Voltage is sensed and it is compared with the reference voltage. The error is applied to the PI/FOPID/PR Controller. The PI/FOPID/PR updates the pulse width of ILBC to regulate the load voltage.

SYSTEM ANALYSIS
Design is done by obtaining the values of V 1, I 1 and frequency of MOSFET. Based on required capacitor voltage, the duty ratio is calculated using the following equation Efficiency of the converter to calculatethe output current is The values of L & C are calculated by assuming Voltage to be injected is equal to IZ. The active filter is designed to supply fifth harmonic. The value of C 5 is assumed and L 5 is calculated with formula ( 5 ) Pulse width for switches of DVR inverter is . Pulse width for switches of AF inverter is Total Input current of ILBC is sum of the currents through L 1 and L 2. I T =I L1 + I L 2 (6) The output of FOPID is as follows Where m and n are fractions. The output of PR based system is as follows.
V S E S K K   Fig 3.1.Line impedance is split into two equal parts. Initial load and additional load are represented as series combination of R & L. Additional load is connected with the help of Breaker-1. Voltage of DVR is injected using Breaker -2. SAF part of UPQC is connected at the sending end of the system. The Output of DVR is injected into the line through a transformer. Load voltage is rectified to convert it to an analog signal. It is compared with the reference voltage. The error is applied to a PI controller. The output of PI controller is applied to pulse generator. The receiving end voltage is shown in Fig.3.2 and its peak value is 10 4 Volts. The R.M.S receiving end voltage is shown in Fig.3.3 and its value is 6900 Volts. The Real power is shown in Fig 3.4 and its value is 4 * 10 5 Watts. The Reactive power is shown in Figure 3.5 and its value is 6 * 10 4 VAR.

V.
CONCLUSIONS PI, FOPID & PR based ILBC-UPQC systems are modeled and simulated using MATLAB and the results are analyzed. The results indicated that the response with PR is faster than that of PI& FOPID Controlled ILBC-UPQC systems. The settling time is reduced by 0.06 sec when compared with PI and reduced by 0.02 sec when compared with FOPID. The steady state error is reduced by 2.6 Volts by replacing PI with FOPID Controller and also reduced by 0.9V by replacing FOPID with PR controller. The contributions of the present work are as follows: ILBC based UPQC is proposed for power quality improvement. The PR is proposed to enhance time domain response characteristics of ILBC based UPQC system. The advantages of proposed ILBC-UPQC system are reduced ripple and improved time domain response characteristics.The disadvantage is that the hardware of ILBC becomes twice that of HSUC.
The present work deals with comparison of PI, FOPID controlled ILBC-UPQC systems with PR based ILBC-UPQC system. The comparison between PR & FUZZY controlled systems will be done at a later date.