Title: Performance evaluation of interleaved high‐gain converter configurations
Abstract: IET Power ElectronicsVolume 9, Issue 9 p. 1852-1861 Research ArticlesFree Access Performance evaluation of interleaved high-gain converter configurations Hyuntae Choi, Corresponding Author Hyuntae Choi [email protected] Australian Energy Research Institute and School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, 2052 NSW, AustraliaSearch for more papers by this authorMinsoo Jang, Minsoo Jang Australian Energy Research Institute and School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, 2052 NSW, AustraliaSearch for more papers by this authorMihai Ciobotaru, Mihai Ciobotaru Australian Energy Research Institute and School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, 2052 NSW, AustraliaSearch for more papers by this authorVassilios G. Agelidis, Vassilios G. Agelidis Australian Energy Research Institute and School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, 2052 NSW, AustraliaSearch for more papers by this author Hyuntae Choi, Corresponding Author Hyuntae Choi [email protected] Australian Energy Research Institute and School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, 2052 NSW, AustraliaSearch for more papers by this authorMinsoo Jang, Minsoo Jang Australian Energy Research Institute and School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, 2052 NSW, AustraliaSearch for more papers by this authorMihai Ciobotaru, Mihai Ciobotaru Australian Energy Research Institute and School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, 2052 NSW, AustraliaSearch for more papers by this authorVassilios G. Agelidis, Vassilios G. Agelidis Australian Energy Research Institute and School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, 2052 NSW, AustraliaSearch for more papers by this author First published: 01 July 2016 https://doi.org/10.1049/iet-pel.2015.0644Citations: 9AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract This study presents the experimental verification of an interleaved high-gain (IHG) DC–DC converter using series and parallel configurations. The interleaved configurations allow the converter to achieve high voltage gain and high current rating, thus increasing the power rating of the converter. Analytical expressions for the design of these interleaved converter configurations are included in the study. The efficiency of the IHG DC–DC converter is increased due to the zero-voltage switching of all active switches and the zero-current switching of all diodes. Experimental results taken from three 1 kW prototypes with different configuration (non-interleaved, and series and parallel interleaved) are presented to verify the interleaving performance and efficiency. Moreover, the effect of soft-switching in terms of efficiency is demonstrated. 1 Introduction High-gain DC–DC converters have benefit for many applications including solar photovoltaic (PV) power system. Generally, the integration of the power from distributed PV systems into the existing electricity grid has been made with either single-stage (without DC–DC converter) [1-3] or two-stage conversion (with a step-up DC–DC converter) [4-7]. The PV system configurations using two-stage conversion are preferable for residential applications which have received increasing popularity in the past decade [8]. For residential PV applications, which are characterised as low-power and high-efficiency applications, transformerless configurations become more advantageous due to their smaller and lighter design, lower cost and higher efficiency [9-11]. Thus, a high voltage conversion ratio is required for DC–DC converters for transformerless configurations, which boosts the relatively low output voltage of PV panels (40–60 V) to a higher voltage (400–500 V), which meets the requirements of residential PV inverter applications [12]. Conventional transformerless boost converters cannot achieve such voltage conversion ratios and thus, a number of high-gain DC–DC converter topologies have been proposed in the technical literature [13-27]. To increase the voltage conversion ratio, switched-capacitor converters have been proposed in [13-15]. The switched-capacitor technology increases the voltage conversion ratio and decreases the voltage stress of the devices. Although the switched-capacitor technique does not involve magnetic components, the converters suffer pulsating input currents. Several switched-capacitor converters with continuous input current were proposed in [16, 17]. However, converters need more components than conventional boost converter to achieve high voltage gain. Coupled-inductor converters are an alternative solution for obtaining high gain [18-20]. The considerably high gain of such converters is achieved by the coupled inductor acting as a transformer. However, the converter efficiency is degraded due to the large input current ripple and energy losses of the leakage inductance. Interleaved coupled-inductor converters have been proposed in [21-25]. The interleaved configuration supports an increase of the converter power rating, but the converter layout is constrained and the design procedure is relatively complex. Simplified interleaved coupled-inductor converter topologies were introduced in [26, 27]. Other alternatives for achieving high voltage gain, interleaved boost converter [26] and boost converter with voltage multiplier cell [28] were proposed. A magnetically coupled voltage-doubler circuit is introduced in [26], while series or parallel configuration of voltage multiplier cell is introduced in [28]. High-gain multi-input converters for energy storage system are proposed in [29, 30]. Soft-switched boost converter was proposed in [31]. The converter achieves high voltage gain by introducing an auxiliary circuit to the conventional boost converter. Although conceptual circuit diagrams of the interleaved configurations were presented in [31], a detailed analysis as well as the operation principle of interleaved configuration were not reported. In addition, no simulation results and experimental verification of the interleaved configuration of such high-gain converter were performed. The main objective of this paper is to experimentally verify the operation of the interleaved high-gain (IHG) DC–DC converter. At the same time, a detailed analysis and the operation principle of IHG converter are reported. The high voltage gain and power rating capabilities of this interleaved converter makes it suitable for two-stage conversion transformerless PV applications. The design guidelines of the converter for such application are presented. In this paper, simulation and experimental results are provided to validate the performance of the IHG DC–DC converter for two different interleaved configurations (parallel expansion and series expansion). The rest of the paper is organised as follows: Section 2 describes the high-gain interleaved DC–DC converter. Simulation results and experimental verification of three different IHG converter configurations are presented in Sections 3 and 4, respectively. Finally, the conclusions are summarised in Section 5. 2 IHG DC–DC converter 2.1 Converter topology The circuit configuration of high-gain converter is shown in Fig. 1a. The converter substitutes a rectifier diode of the conventional boost converter with a switch (ST) and introduces an auxiliary circuit, which is composed of an inductor (Lau), a capacitor (Cau) and a voltage doubler circuit. The voltage doubler circuit comprises two diodes (DT and DB) and a capacitor (CT). The auxiliary circuit allows the converter to have a higher voltage gain than the conventional boost converter, and helps to achieve zero-voltage switching (ZVS) of lower switch SB and upper switch ST. Additionally, zero-current switching (ZCS) of the voltage doubler diodes is achieved by discontinuous conduction mode operation of inductor Lau. Fig. 1Open in figure viewerPowerPoint IHG converter a Basic module (N = 1, P = 1) b Series extension (N = 2, P = 1) c Parallel extension (N = 1, P = 2) The converter configuration can be extended to an interleaved configuration, and extension examples of the converter are shown in Figs. 1b and c, where N is the number of series-connected voltage doublers and P is the number of parallel-connected diode legs of the voltage doubler. Higher voltage gain can be achieved by increasing N, while elevated current rating of the converter can be accomplished by increasing P. At the same time, the input current ripple is reduced as N and P increase. On the basis of the analysis of the non-interleaved converter reported in [31] (N = 1, P = 1), a generalised analysis of the interleaved converter (N ≠ 1 and P ≠ 1) is derived here. Assuming that the voltages across the capacitors are constant during the switching period Ts, the output voltage is given by (1)where n = 1, 2, …, N. Voltages across the output capacitors and can be expressed as (2) (3)where Vi is the input voltage and is the voltage drop on CT_n caused by the duty-cycle loss Dloss, which can be defined as (4)where are the duration of the positive and negative voltage peaks at Lau, respectively. Fig. 6b shows the voltage waveform of Lau and duty-cycle loss terms . The duration of is dominantly affected by the values of Lau: the bigger the inductance Lau is, the longer the duration . This duty-cycle loss reduces the effective duty ratio which can be derived by (5)Although the converter operates using D, the output voltage of the converter needs to be calculated using Deff. Thus, the output voltage can be expressed as (6) (7)From (4) and (6), the voltage drop can be obtained by (8)Meanwhile, since the average current through Cau_n,p is zero, the output current equals the average current of DT_n,p and DB_n,p can be derived as (9) (10)where p = 1, 2, …, P and, are the positive and negative peak values of inductor current, respectively. The peak current values are given by (11) (12)The difference between the input inductor current and the auxiliary inductor current is the main independent variable for the ZVS operation of switches SB_n,p and ST_n,p. To ensure the ZVS operation of , the following condition should be satisfied (13)where are the drain–source capacitance of SB_n,p and ST_n,p, respectively. The ZVS operation of ST_n,p is achieved when the following condition is satisfied (14)Equations (13) and (14) could be satisfied with small Lin_n,p and large Lau_n,p. However, reducing Lin_n,p will increase the input current ripple, and increasing Lau_n, p will elevate the duty-cycle loss, which will affect the voltage gain of the converter. 2.2 Operating principle Key waveforms of IHG converter (N = 2, P = 1) are shown in Fig. 2. The waveforms of IHG converter (N = 1, P = 2) are very similar to IHG converter (N = 2, P = 1), thus only one figure is presented. Complementary gate signals are applied to the top and bottom switches and 2π/(N × P) phase shifted switching signal applied to each interleaved switch leg. On the basis of the switching state and the polarity of the auxiliary currents , certain diodes are conducting and the current path is established. When the bottom switch is turned on, is increased from negative value to positive value and vice versa when the top switch is turned on. The ZVS operation of all switches is achieved when changes its direction. The ZCS operation of diodes is realised when changes its polarity. The converter operation can be divided into eight modes based on the auxiliary inductor currents, and the equivalent circuit of the eight different operating modes of IHG converter is shown in Fig. 3. Each mode contains two current paths due to interleaving and each current path charging one of output capacitors. Fig. 2Open in figure viewerPowerPoint Key waveforms of the IHG converter (N = 2, P = 1 or N = 1, P = 2) Fig. 3Open in figure viewerPowerPoint Operation modes a IHG converter (N = 2, P = 1) b IHG converter (N = 1, P = 2) 2.3 Converter characteristics The relationship between the voltage gain and duty ratio of the conventional boost converter and IHG converters with different N using (7) is illustrated in Fig. 4a. The voltage gain of the IHG converter is N + 1 times higher when compared with a conventional boost converter. Fig. 4Open in figure viewerPowerPoint Characteristics of IHG converter a Voltage gain of IHG converters (P = 1, N = 1, 2, 3) and conventional boost converter b Input current ripple of IHG converter The interleaved asymmetrical pulse-width modulation switching technique is applied to the converter, which results in asymmetrical ripples in the input inductor current. Fig. 4b shows the relationship between the input current ripple and the duty ratio of the IHG converter. The input current ripple can be expressed as (15) (16) (17)The voltage ripple on output capacitors CT_n and CO can be derived by (18) (19)One disadvantage of increasing N is the voltage across the auxiliary capacitors, which can be derived as (20)The voltage rating of each auxiliary capacitor is different and the upper most auxiliary capacitor Cau_N, P has the highest voltage rating as follows (21) 2.4 Design guideline The design of an IHG converter requires careful consideration of several important factors: converter configuration input and auxiliary inductance, auxiliary and output capacitance and switching frequency. In this paper, the selection of converter configuration and the design procedure for 1 kW IHG converter (N = 1, P = 1) are given as an example. Greater values of P allow the converter to reduce the current rating of components. At the same time, the input current ripple is reduced by a factor of 1/P, and can be reduced further depending on duty cycle. The reduced input current ripple improves the performance of maximum power point tacking in PV application [32]. Although increasing P can provide such advantages, it also involves increased circuit complexity and higher components count. The relationship of components count, input current ripple and power rating with respect to P is summarised in Table 1. When selecting a proper P, the converter power rating should be considered first, and then the other parameters, such as current ripple size and component count. Table 1. Component count, input current ripple and power rating of converter with different values of P P = 1 P = 2 P = 3 component count 9 16 24 input current ripple ΔI ΔI/2 ΔI/3 converter power rating Pc 2Pc 3Pc Choosing a proper value for N is also an important factor when designing an IHG converter. The voltage conversion ratio of the converter is increased by a factor of N. Moreover, the input current ripple is decreased by a factor of 1/N. However, N is limited due to the voltage rating of the auxiliary capacitor. As described in (20), the voltage rating of the upper most auxiliary capacitor increases by increasing N. Therefore, N should be properly chosen considering a trade-off between converter voltage gain, input current ripple and voltage rating of auxiliary capacitor. The input voltage range and the required output voltage have been determined by the characteristic of the PV applications. In this paper, output voltage is boosted from 40–80 V input voltage to 600 V and switching frequency (fs) is 80 kHz. The inductance value for input and auxiliary inductor should be calculated according to the current rating and the current ripple. The input inductance Lin can be calculated using (15) with input current ripple (Δii) of 30%. Once Lin is set, the minimum auxiliary inductance Lau for ensuring ZVS operation is calculated using (11)–(14). As described before, the minimum value of Lau should be considered to minimise the duty loss which reduces the voltage gain. A value of 130 µH is selected for Lin and 12 µH for Lau. The output capacitors (CT_1 and CO) are chosen based on (18) and (19) with respect to the voltage rating. Since the output voltage is 600 V and N = 1, the output capacitor voltage rating is 300 V. A value of 25 µF is selected for CT_1 and CO considering a maximum of 5% voltage ripple. The voltage rating of auxiliary capacitor Cau is calculated using (20) or (21). A value of 5 µF is selected for Cau considering a maximum of 5% voltage ripple. 3 Simulation results This section presents the efficiency and duty comparison of two different IHG converter configurations. The IHG converter models have been implemented and simulated using MATLAB/Simulink [33] and PLECS [34]. The parameters of the IHG converter are selected following the design guidelines presented in Section 2 and are summarised in Table 2. The simulation analysis focused on comparing the converter efficiency for different voltage gains and switching frequencies. For a more accurate comparison regarding efficiency, the following resistances were considered: on-state resistance of switches, inductor copper losses and series equivalent resistance of capacitors. Table 2. Specifications for the IHG converter (N = 1, P = 1) Simulation model Experimental model rated power, kW 1 1 input voltage Vi, V 40–80 40–80 output voltage Vo, V 600 600 switching frequency fS, kHz 50–90 80 input inductor Lin, µH 130 130 auxiliary inductor Lau, µH 12 12 auxiliary capacitor Cau, µF 5 5 output capacitors CT and CO, µF 25 25 Fig. 5a shows the efficiency of the IHG converter (N = 1, P = 1) for different voltage gains and switching frequencies. As can be seen, the converter has better efficiency for smaller voltage gains, and the efficiency varied from 96.9 to 98.5% at 50 kHz. The relationship between the duty cycle, voltage gain and switching frequency is shown in Fig. 5b. The ideal maximum duty cycle to achieve a voltage gain of 15 is 0.87, but the actual maximum duty cycle is higher than 0.9 for all switching frequencies due to duty-cycle losses. Fig. 5Open in figure viewerPowerPoint Simulation results of IHG converter a Efficiency of IHG converter (N = 1, P = 1) as a function of voltage gain and switching frequency b Duty cycle of IHG converter (N = 1, P = 1) as a function of voltage gain and switching frequency c Efficiency of IHG converter (N = 2, P = 1) as a function of voltage gain and switching frequency d Duty cycle of IHG converter (N = 2, P = 1) as a function of voltage gain and switching frequency The efficiency of the IHG converter (N = 2, P = 1) is shown in Fig. 5c. Similar to IHG converter (N = 1, P = 1), the efficiency of the IHG converter (N = 2, P = 1) decreases as the voltage gain is increased, but the efficiency variation range at 50 kHz (96.71–98.04%) is slightly smaller than for the IHG converter (N = 1, P = 1). The efficiency of the converter is affected by the switching frequency, and the maximum efficiency is achieved at 50 kHz. Fig. 5d shows the relationship between duty cycle, voltage gain and switching frequency. The duty cycle variation of the IHG converter (N = 2, P = 1) with respect to the switching frequency is higher than for the IHG converter (N = 1, P = 1). Moreover, the duty cycle required to achieve a voltage gain of 15 is 0.87 at a switching frequency of 50 kHz, and varies following the change of switching frequency. This dependency on switching frequency of the IHG converter (N = 2, P = 1) is higher than for the IHG converter (N = 1, P = 1) and is due to the number of output capacitors whose voltages are affected by the duty cycle loss. The IHG converter (N = 2, P = 1) has two output capacitors whose voltages are influenced by the duty cycle loss, whereas only one output capacitor is affected in the case of the IHG converter (N = 1, P = 1). The higher switching frequency generates more duty cycle loss, which reduces the voltage level of the output capacitors. The IHG converter (N = 1, P = 1) requires a duty cycle >0.8 to achieve the voltage gain necessary to match the Maximum Power Point (MPP) voltage range, making it unsuitable for PV application. In contrast, the IHG converter (N = 2, P = 1) requires a duty cycle <0.8 under the same condition. Increasing switching frequency slightly decreases converter efficiency, although the ZVS range is extended. 4 Experimental results The following section presents experimental verification of an IHG converter prototype. Three different configurations of the IHG converter have been built: N = 1, P = 1; N = 2, P = 1; and N = 1, P = 2, which are shown in Figs. 1a–c, respectively. The parameters of the IHG converter have been chosen based on the simulation models, and are summarised in Table 2. A powered toroid core, model Kool Mµ 0077908A7 and type 2 litz wire were selected for inductor Lin to reduce the core and copper losses. A Kool Mµ toroid 0077439A7 core and the same litz wire were chosen for inductor Lau. On the basis of (18)–(21), 5 µF, 450 V film capacitor was chosen for Cau, and 25 µF, 450 V film capacitors were selected for both CT and CO. The switches were CREE CMF20120D SiC MOSFETs, and CREE C4D20120A Schottky diodes were used for diodes DT and DB. Experimental results for the IHG converter (N = 1, P = 1) are presented in Figs. 6 and 7. The input/output voltage and current of the converter are shown in Fig. 6a. The output voltage of the converter is 600 V, thus the converter achieves a gain of 7.5 for a duty ratio of 0.78, which is nearly double that of the conventional boost converter. Fig. 6b shows the voltage and current waveforms of the auxiliary inductor Lau. The duration of the voltage peak at Lau depends on Lau; a higher inductance value leads to a longer duration voltage peak, which reduces the effective duty cycle. At the same time, it increases the ZVS region of the switches. The ZVS operation of both upper and lower switches is shown in Figs. 7a and b. The ZCS operation of the two diodes is illustrated in Figs. 7c and d. Fig. 6Open in figure viewerPowerPoint Experimental results of IHG converter (N = 1, P = 1) a Input and output voltages and currents b Voltage and current of auxiliary inductor Lau_1,1 Fig. 7Open in figure viewerPowerPoint Experimental results of IHG converter (N = 1, P = 1) a Voltage and current of upper switch ST_1,1 b Voltage and current of lower switch SB_1,1 c Voltage and current of upper diode DT_1,1 d Voltage and current of lower diode DB_1,1 The IHG converter (N = 1, P = 2) is capable of handling double the amount of current than the IHG converter (N = 1, P = 1) using the same component specifications. Fig. 8a shows the input and output voltage and current of the IHG converter (N = 1, P = 2). As with the IHG converter (N = 1, P = 1), the IHG converter (N = 1, P = 2) has a voltage gain of 7.5 with a duty ratio of 0.78. Fig. 8b shows the input current Ii and input inductor currents. As mentioned before, asymmetrical ripples in the input inductor current reduce the input current ripple. The ZVS operation of the switches is shown in Figs. 9a and b. Figs. 9c and d illustrate the ZCS turn-off of the four diodes. One notable point is that, for the same input current, the current ratings of the switches and diodes are halved compared with the IHG converter (N = 1, P = 1). Fig. 8Open in figure viewerPowerPoint Experimental results of IHG converter (N = 1, P = 2) a Input and output voltages and currents b Input current Ii and current of input inductors Lin_1,1 and Lin_1,2 Fig. 9Open in figure viewerPowerPoint Experimental results of IHG converter (N = 1, P = 2) a Voltage and current of upper switches ST_1,1 and ST_1,2 b Voltage and current of lower switches SB_1,1 and SB_1,2 c Voltage and current of upper diodes DT_1,1 and DT_1,2 d Voltage and current of lower diodes DB_1,1 and DB_1,2 The IHG converter (N = 2, P = 1) uses the same specifications as the IHG converter (N = 1, P = 1), except for the upper auxiliary capacitor Cau_2,1. Due to the different voltage rating mentioned in Section 3, a 5 µF, 900 V film capacitor is used instead of a 5 µF 450 V capacitor. Fig. 10a shows the input and output voltage and current of the IHG converter (N = 2, P = 1). The output voltage is around 600 V and the duty ratio is 0.64. Fig. 10b shows the input current and input inductor currents. As for the IHG converter (N = 2, P = 1), asymmetrical ripples in the input inductor current reduce the input current ripple. The voltages across the auxiliary capacitors are shown in Fig. 10c. The voltage across the upper auxiliary capacitor is almost double that of the lower auxiliary capacitor. The ZVS operation of the upper and lower switches is shown in Figs. 11a and b. The switch voltages are the same as for the IHG converter (N = 1, P = 1), while the output voltage is increased. The diode voltages and currents are illustrated in Figs. 11c and d, which show the ZCS operation of all diodes. Fig. 10Open in figure viewerPowerPoint Experimental results of IHG converter (N = 2, P = 1) a Input and output voltages and currents b Input current Ii and current of input inductors Lin_1,1 and Lin_2,1 c Voltage across auxiliary capacitors Cau_1,1 and Cau_2,1 Fig. 11Open in figure viewerPowerPoint Experimental results of IHG converter (N = 2, P = 1) a Voltage and current of upper switches ST_1,1 and ST_2,1 b Voltage and current of lower switches SB_1,1 and SB_2,1 c Voltage and current of upper diodes DT_1,1 and DT_2,1 d Voltage and current of lower diodes DB_1,1 and DB_2,1 As described in Section 2, the converter needs to operate with a variable input voltage, while the output voltage needs to be maintained at a specified level. Fig. 12a shows the relationship between duty ratio and input voltage of three different configurations of IHG converter, while maintaining the output voltage at 600 V. As can be seen, all three converter configurations are able to operate with a variable input voltage; however with a low input voltage, the IHG converter (N = 1, P = 1) and IHG converter (N = 1, P = 2) require extremely high duty ratios to achieve the required voltage gain. Therefore, converter configurations with N = 1 are not suitable for PV applications and N should be higher than 1. Fig. 12Open in figure viewerPowerPoint Experimental results of IHG converter a Input voltage and duty ratio of three different IHG converters b Efficiencies of three different IHG converters c Efficiencies of IHG converter (N = 1, P = 1) under two different conditions The efficiencies of the three different configurations of IHG converter are shown in Fig. 12b. At rated load, the IHG converter (N = 2, P = 1) has the highest efficiency of 95.5%, while the other two topologies have efficiencies of 94.8%. At a load of 500 W, the IHG converter (N = 1, P = 1) has the highest efficiency of 96.5%. Efficiencies of all three converter topologies remain above 94% for most of the load range. To verify the effect of soft-switching, efficiency of the IHG converter (N = 1, P = 1) is measured under two different conditions: soft-switched operation and hard-switched operation. Hard-switching of the switches is realised by reducing the auxiliary inductance from 12 to 6 µH. two measured converter efficiencies are shown in Fig. 12c. As can be seen, the soft-switching operation improves converter efficiency more than 2%, and the effect of it is more significant at light load conditions. 5 Conclusions The experimental verification of three IHG DC–DC converters with different configuration has been presented in this paper. At the same time, the operation principle as well as the detailed analysis of the IHG converter has been reported. The interleaved configurations allow the converter to achieve high voltage gain and increased power rating. These capabilities make the IHG converter suitable for PV applications. Efficiency comparisons based on different switching frequencies and voltage gains have been presented using simulation results. The converter demonstrated higher efficiency at lower switching frequency and lower voltage gain. Experimental results verified the operation characteristics of the IHG converter. Three different configurations of IHG converter have achieved both ZVS and ZCS operation of the switches and diodes, respectively. The efficiency of all three IHG converters was higher than 94% for most of the operation range, with the highest efficiency of 96.5% being achieved. The use of soft-switching technique significantly improved the converter efficiency. 6 References 1Singh B., Jain C., and Goel S.: ‘ILST control algorithm of single-stage dual purpose grid connected solar PV system’, IEEE Trans. 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Publication Year: 2016
Publication Date: 2016-07-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 15
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