Module Integrated Converter Research Articles

Controller Synthesis of Aperiodic Sampled-Data Networked Control System With Application to Interleaved Flyback Module Integrated Converter

Controller Synthesis of Aperiodic Sampled-Data Networked Control System With Application to Interleaved Flyback Module Integrated Converter

Thermal management in high-frequency, high-power density, solar PV integrated GaN converter system

The High-Frequency and High-Power Density (HPD) converters are the choices of the module integrated Solar Photo Voltaic (SPV) for standalone and interconnected renewables. The operation of the Module Integrated Converters (MIC) in these conditions facilitates better electrical characteristics but care is to be taken in designing the thermal management as the conditions are harsh and vary from that of the non-integrated. The unique design starts from the circuit operations, device packaging, component placement, thermal options with a selection of elements, and finally the airflow control methods. A 300 W, Poly-phase Synchronous Boost Converter with Gallium Nitride devices, operating at 500 kHz is designed for the module integrated conditions in a fixed standalone operation. The EPC-GaN device is used, enabling an effective dual dissipative thermal management, compared to conventional methods. A single heat-sink design for the six devices of the converter in common for effective dissipation through the case is presented. Further, methods for improved dissipations through PCB were explained. An adaptive digital controlled method of airflow control to maintain the acquired-ambient, for the endured operations of the MIC, is discussed. Finally, a stable, high-power density, MIC with 64.3 W/in3, is designed and demonstrated for a standalone street lighting application.

High Efficiency and Full MPPT Range Partial Power Processing PV Module-Integrated Converter

To increase the energy yield of PV systems in presence of module level power mismatches, Maximum Power Point Tracking (MPPT) should be performed by converters at module level. Using module level converters at the output of the PV panels adds a constant loss even when there is no power mismatch which increases the overall system losses and compromises part of the energy yield improvement. To decrease this constant loss especially when there is no power mismatch, Partial Power Processing (PPP) concept is used in this paper to achieve a new high-frequency and high-efficiency module integrated PV converter, which can achieve full range MPPT and maximum possible efficiency when there is no mismatch. To overcome the challenge of limited MPPT range for partial power converters a special Pulse Density Modulation (PDM) technique is proposed, which preserves the merits of PPP and renders full range MPPT. A 220 W prototype converter is implemented to justify the converter principal of operation and analyses. The proposed converter reached 99.6% to 96.5% efficiency for the power mismatches in the PV module ranging from 0 to 50% of the maximum module power generation capability, respectively. The efficiency drop is shown to be linear with power mismatch level without any abrupt reductions that is commonly observed in conventional PV module integrated converters.

Integrated differential power processing converters for PV systems

Nowadays the growth of Module Integrated Converters (MIC) concept is increasing. This concept was developed for PV applications to improve the efficiency of the converters. In this paper we propose a submodule MPP tracking algorithm to track the maximum power from the partially shaded cells. Generally, PV module have three submodules. Each submodule is formed by series connection of two strings. Here we take a different P&O algorithm for each submodule to track maximum power from the all three submodules. Each submodule will have their own DC-DC converter. In DC stage, DC-DC converters are connected in three configurations to serve sufficient energy to inverter for single phase grid connected systems.

Soft-Switching High Step-Up DC–DC Converter Based on Switched-Capacitor and Autotransformer Voltage Multiplier Cell for PV Systems

This article introduces a nonisolated, high step-up voltage multiplier cell (VMC)-based dc–dc converter for applications such as module-integrated converter and power optimizers. The VMC combines switched capacitor with autotransformer techniques and active clamp circuit. The autotransformer tertiary winding is employed to increase voltage gain without operating the main switch under extreme duty cycle condition, to reduce the current through the main switch before it turns <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> and to ensure its zero-voltage switching (ZVS) operation on a wide operation range. The auxiliary switch in the clamp circuit provides ZVS for the main switch and vice-versa. Thus, both switches are turned <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> with zero voltage and there is no switching loss. Hence, high switching frequency is used to reduce the passive components’ volume and weight. Besides, the low dc-bias and bidirectional magnetizing current allows a smaller magnetizing inductance in the autotransformer to further minimizing the dimensions of the magnetic core. The leakage inductances are used to provide zero-current switching condition for the diodes, eliminating their reverse-recovery losses. The operation principle, steady-state analysis, and design guidelines are depicted and validated through experimental results obtained from a 350-W prototype of the proposed converter. Efficiency of 96.5% at full load is also reported.

An Overview of Voltage Boosting Techniques and Step-Up DC-DC Converters Topologies for PV Applications

The development of technologies to improve the performance of photovoltaic (PV) module integrated converters (MICs) is fundamental to increase the use of distributed generation systems with photovoltaic power source in large urban centers, mainly for complex residential roofs. For two-stage PV MICs, high step-up DC-DC converters are required to boost the low PV module voltage to a higher voltage, in order to suit the DC bus voltage requirements of grid-tied inverters. Thus, to support researchers interested in developing DC-DC power conversion for PV microinverters, this paper classifies the DC-DC converters according to their operational and constructive characteristics and presents some elementary voltage-boosting techniques to aid in analyzing and understanding more complex topologies. Finally, high step-up DC-DC converters based on magnetic coupling and switched capacitor widely cited by important works related to PV applications are presented, with their principles of operation analysed in a simple and objective way, but sufficient to understand their capability to provide high voltage gain. The approach presented by this paper leads to insight into how to place the energy storage elements to create new topologies of DC-DC converters, so that high voltage gain is achieved, and how to analise the high voltage gain capability of complex topologies

PV Mismatch 보상용 PV Optimizer MPPT 제어 알고리즘 설계

This paper includes on the development of a PV Optimizer. The PV optimizer is designed as an MIC (Module Integrated Converter) using P&O algorithm to track a maximum power point. It compensates the power loss from mismatch of the panels. The mismatch occurs due to partial shading because of clouds or other environment conditions in PV panel with serial string structure. The PV optimizer can be operated as a buck converter. The buck converter operation range is limited by its MPPT operational characteristics. The Maximum Power Point Tracking (MPPT) is also controlled under the mismatch using the developed embedded program. Using the PV Simulator and TerraSAS program, It is experimented under a situation that solar radiation rapdly changes due to partial shading. It is verified that the developed PV Optimizer increases the power efficiency to about 20% and the MPPT efficiency is measured up to 99.87%.

Analysis, Design, and Implementation of the AFZ Converter Applied to Photovoltaic Systems

Grid-tied photovoltaic (PV) installations with distributed maximum power point tracking (DMPPT) architectures include a dc-dc module integrated converter (MIC) for managing each PV panel, isolating it from the others, reducing the mismatching effect and maximizing the harvested power. In this article, the autotransformer forward converter with type-Zeta resonant reset (AFZ) is proposed as a DMPPT architecture's MIC candidate. The main characteristics of the AFZ converter are the high versatility due to its voltage step-up and step-down capability; the use of an optimized autotransformer with only two windings, reducing the complexity and power losses of this component; the good dynamic performances, like the forward converter ones; the low number of components and the simplicity and high feasibility associated to the use of just one active switch. Besides, soft switching transitions are achieved thanks to the autotransformer type-Zeta resonant reset. The steady-state theoretical analysis, considering the effect of the autotransformer leakage inductance, is presented. The converter is also studied in the frequency domain, obtaining the small-signal transfer functions. A design procedure based on the requirements of a 100-kW grid-tied photovoltaic installation is described, yielding in a 225-W prototype with efficiencies up to 95.6%. Experimental results validate the theoretical analysis.

Current-Source Single-Phase Module Integrated Inverters for PV Grid-Connected Applications

This paper presents a modular grid-connected single-phase system based on series-connected current-source module integrated converters (MICs). The modular configuration improves the reliability, redundancy and scalability of photovoltaic (PV) distributed generators. In this system, each PV panel is connected to a dc/ac inverter to permit individual Maximum Power Point Tracking (MPPT) operation for each panel. Thus, the harvested power from the PV system will increase significantly. There are four different inverter topologies suitable to be used as MICs with different performances in terms of filtering elements size, power losses, efficiency, output voltage range, and high frequency transformers’ size. For the MPPT control, the oscillating even order harmonic components should be eliminated from the inverter’s input side otherwise the maximum power cannot be extracted. The proposed modulation scheme in this paper will ease the control of inverter’s input and output sides. Therefore, the 2nd order harmonic in the input current can be eliminated without adding new active semiconductor switches. A repetitive controller coupled with proportional-resonant controllers are employed to achieve accurate tracking for grid side as well as input side currents. Comparisons and performance evaluations for the proposed MICs are presented and validated with 1 kVA prototype controlled by TMS320F29335 DSP.

Module-Integrated Converter Based on Cascaded Quasi-Z-Source Inverter With Differential Power Processing Capability for Photovoltaic Panels Under Partial Shading

Conventional microinverter or module-integrated converter (MIC)-based photovoltaic (PV) systems are prone to be complex and costly because each MIC requires not only a boost converter to bridge a huge voltage gap between a PV panel and grid but also desirably a differential power processing (DPP) converter to preclude partial shading issues. This paper proposes a novel MIC based on cascaded quasi-Z-source inverters (qZSIs) with DPP capability. A traditional qZSI and voltage multiplier (VM)-based DPP converter are integrated into a single unit with sharing active switches and magnetic components, achieving system- and circuit-level simplifications. In addition, a novel control strategy utilizing two control freedoms of shoot-through duty cycle $d_{st}$ and modulation index M to simultaneously perform maximum power point tracking (MPPT) and DPP function, respectively, is also presented. A 150 W prototype for a standard PV panel consisting of three substrings is built, and experimental tests are performed emulating partial shading conditions. The results demonstrate that the proposed integrated qZSI could perform MPPT with satisfactory preventing partial shading issues while generating ac voltage at the inverter output.

Module Integrated PV Balancer for PV Applications

This paper presents the possibility of Module Integrated Converters (MIC) called PV balancers for photovoltaic applications. The proposed thought enables self-governing Maximum Power Point Tracking (MPPT) for each board, and radically decreases the requirements for power converters. The power rating of a PV balancer is under 20% of its accomplices, and the collecting cost is as such inside and out diminished. The proposed engineering of the PV balancer is checked through simulation results. It is foreseen that the proposed methodology will be an ease answer for future photovoltaic power frameworks.

Analysis and implementation of the Autotransformer Forward-Flyback converter applied to photovoltaic systems

The Distributed Maximum Power Point Tracking (DMPPT) architecture is employed to overcome the mismatching phenomena in grid-tied photovoltaic (PV) installations. In this kind of architecture, a DC-DC module integrated converter (MIC) manages each PV panel. Thanks to the DC-DC converters, the differences between PV panels do not influence others, maximizing the amount of harvested power. The MIC requirements to make this kind of solutions profitable are voltage step-down and step-up capability, low cost and high efficiency. This paper analyses the Autotransformer Forward-Flyback (AFF) converter. This converter is considered as a MIC candidate for fulfilling the requirements above. The study of the AFF converter includes the steady-state analysis and the small signal analysis in continuous conduction mode. The advantages of the AFF converter are the capability of voltage step-down and step-up; the simplicity since it only includes a single controlled switch; the use of an autotransformer; good dynamic performances and the soft switching characteristics in all the diodes. The paper includes a detailed AFF converter step-by-step design procedure, applied to 100 kW grid-tied PV installation, in which the effect of shadows has been considered. A 225 W AFF converter prototype validates the theoretical analyses, achieving an efficiency up to 94.5%.

A PV Module Integrated Converter for Enhanced Perfomance in Standalone and DC Microgrid Applications

The aim of these design toward plot and execute greatest power point following (MPPT) that makes utilize of a fluffy rationale control algorithm. Fluffy rationale, via using dealing with nonlinearities, gives a regular controller used for this form of utilization. The technique likewise income by the heuristic way to deal with the problem that beats the intricacy in demonstrating nonlinear frameworks. Therefore as to perform this objective, MPPT model comprising of a PV module, a DCDC converter, and a fluffy rationale controller become created. Examination of buck, converter as well as buck-support converter attributes changed into done within an effort on the way to distinguish the most appropriate topology. An incorporated copy of the PV module along with the distinguished converter became reproduced also the effects worn to determine the grasp studying predicted near devise also music the fluffy rationale regulator. The regulator changed into veiled the same as an ongoing control application and the MPPT finished via a dc-dc converter constrained by means of a microcontroller. These results in progressed productiveness in favor of the hobby of a photovoltaic strength framework considering battery may be accurately charged and applied in the course of times of low sunlight based radiation. The better productiveness is relied upon to set off essential value funding funds over the long haul. The well known price is saved low through choosing segments that take into account executing the capacities requiring little to no effort. Reenactment outcomes demonstrate the high estimation of the element coordinated converter for DC unbiased and microgrid packages. A 400 W model changed into completed by 0.14 Euro/W. Testing established efficiencies over 95% thinking about every misfortunes from have an effect on trade, fuzzy logic MPPT, and estimation and manage hardware.

태양광 전력설비의 효율 향상을 위한 피드포워드 차동전력조절기(DPP)의 적용 검증

Differential power processing (DPP) is a power facility architecture that configures dc - dc converters in parallel with the PV string to improve its power yield. The parallel nature of the DPP architecture brings a number of benefits, such as low converter power rating and low power losses. In this paper, feedfoward DPP structure is applied to improve the efficiency of photovoltaic(PV) power facility. DPP structure is considered to a solution to problems were caused by solar irradiance mismatch. The effectiveness of DPP struture is confirmed by comparing module integrated converter (MIC) structure. Experiments and simulation with feedforward structure using a DSP(TMS320F28335) hardware design were conducted and the improvement in performance with DPP converters was experimentally confirmed.

PV Distributed-MPP Tracking: Total-Cross-Tied Configuration of String-Integrated-Converters to Extract the Maximum Power Under Various PSCs

The building integrated photovoltaic (PV) central inverter architecture comprises various PV module configurations. The PV module configurations are vulnerable to shading effects and cause mismatching power losses. To reduce the detrimental impact of shading and mismatching on energy production, the PV distributed-maximum power point tracking (D-MPPT) architecture has been proposed. In this architecture, an individual dc–dc converter with an MPPT controller is integrated to each PV module for extracting the maximum power. This topology is referred to as module-integrated-converter (M-I-C). In the conventional PV D-MPPT architecture, the output terminals of M-I-Cs are connected either in series or parallel configuration only. The conventional configurations of M-I-Cs have the drawbacks of cross-coupling effects, lower conversion efficiency, two-stage voltage conversion, etc. This paper proposes the total-cross-tied (T-C-T) configuration of string-integrated-converters (S-I-Cs) to overcome the drawbacks of M-I-C configurations. The detailed mathematical analysis of the proposed T-C-T configuration of S-I-Cs is also presented in this paper. The perturb and observe MPPT technique is used for extracting the maximum power. The performance of the proposed T-C-T configuration of S-I-Cs is analyzed under various partial shading conditions and also compared with the PV central inverter architecture as well as with conventional M-I-C configurations.

Solar Module Integrated Converters as Power Generator in Small Spacecrafts: Design and Verification Approach

As small satellites are becoming more widespread for new businesses and applications, the development time, failure rate and cost of the spacecraft must be reduced. One of the systems with the highest cost and the most frequent failure in the satellite is the Electrical Power System (EPS). One approach to achieve rapid development times while reducing the cost and failure rate is using scalable modules. We propose a solar module integrated converter (SMIC) and its verification process as a key component for power generation in EPS. SMIC integrates the solar array, its regulators and the telemetry acquisition unit. This paper details the design and verification process of the SMIC and presents the in-orbit results of 12 SMICs used in Ten-Koh satellite, which was developed in less than 1.5 years. The in-orbit data received since the launch reveal that solar module withstands not only the launching environment of H-IIA rocket but also more than 1500 orbits in LEO. The modular approach allowed the design, implementation and qualification of only one module, followed by manufacturing and integration of 12 subsequent flight units. The approach with the solar module can be followed in other components of the EPS such as battery and power regulators.

Review on Building-Integrated Photovoltaics Electrical System Requirements and Module-Integrated Converter Recommendations

Since building-integrated photovoltaic (BIPV) modules are typically installed during, not after, the construction phase, BIPVs have a profound impact compared to conventional building-applied photovoltaics on the electrical installation and construction planning of a building. As the cost of BIPV modules decreases over time, the impact of electrical system architecture and converters will become more prevalent in the overall cost of the system. This manuscript provides an overview of potential BIPV electrical architectures. System-level criteria for BIPV installations are established, thus providing a reference framework to compare electrical architectures. To achieve modularity and to minimize engineering costs, module-level DC/DC converters preinstalled in the BIPV module turned out to be the best solution. The second part of this paper establishes converter-level requirements, derived and related to the BIPV system. These include measures to increase the converter fault tolerance for extended availability and to ensure essential safety features.

Interleaved boost converter for global maximum power extraction from the photovoltaic system under partial shading

Partial shading (PS) condition has a negative effect on the shaded photovoltaic (PV) modules/arrays itself. In addition, it reduces the output power generated considerably. The PV system configuration represents one of the effective solutions to alleviate the PS effects and extract the global maximum power (GMP) available from the partially shaded PV (PSPV) system. This study introduces a detailed performance analysis and comparisons of four proposed PV system configurations [module integrated converter (MIC), multi-strings interfaced interleaved boost converter (MSIBC), multi-arrays interfaced IBC and single array single converter (SASC)] in terms of output power generated and mismatch loss (MML) index. The selection of the best PV system configuration, which not only mitigates the PS effects but also extracts the GMP available from the PSPV system, depends on a trade-off between the generated power, cost and complexity before judging which one is preferable . Although the MIC PV system has the highest output power generated (33 kW) and MML (100%), it increases the PV system complexity. Whereas, MSIBC has the second highest output power generated (28 kW) and MML compared to MIC. SASC has the lowest generated power and MML among the four configurations. The finding proves that MSIBC has superior performance compared to the other PV system configurations considering both the technical and economic assessment.

Active Cross-Correlation Anti-Islanding Scheme for PV Module-Integrated Converters in the Prospect of High Penetration Levels and Weak Grid Conditions

This paper introduces a new cross-correlation anti-islanding detection scheme for module-integrated converters (MICs) with pseudo dc-link. The proposed scheme periodically injects a second-order harmonic current component of low magnitude (in open-loop mode) and evaluates grid response by means of correlation. The proposed scheme is highly reliable, providing nondetection-zone free operation, fast detection, and compliance with the relevant power quality and anti-islanding standards. Additionally, it excels in lower computational cost, reduced fault detection zone, and higher output power quality, compared to the referenced anti-islanding schemes that are compatible with MICs. Last but not least, it can be implemented in MIC platforms without requiring an output current sensor, being an easily upgradable solution in software level. A firm theoretical framework that considers both high penetration levels of PV systems and weak grid conditions is also included in this paper. The theoretical framework, as well as the effectiveness of the proposed scheme, is verified through extensive experimental results for various electrical-network parameters and nonlinear loading conditions. Finally, a comprehensive comparison between the proposed method and the most common anti-islanding techniques (compatible with MICs) is performed, leading to some valuable conclusions from MICs perspective.

Design and Implementation of New Topology for Solar PV Based Transformerless Forward Microinverter

Recently, transformerless inverters play a vital role for single phase low voltage solar photovoltaic (PV) system due to low cost, lesser weight, small size and high efficiency. However, the leakage current produces electromagnetic interferences, current distortion on the grid with additional losses which affects the performance of the inverter. In this paper, a new inverter topology, to deal with the problem of leakage current is proposed. The various conventional H6 topologies are simulated, compared and evaluated based on the leakage current, performance and safety with the proposed inverter topology. This work focuses on transformerless inverter which is best suitable for module integrated converter (MIC) or microinverter. The proposed topology is employed with unipolar sinusoidal pulse width modulation, and it can reduce the common mode (CM) current. The performance analysis is carried out on different topologies using MATLAB/Simulink environment and the proposed inverter experimentally verified on a 150 W prototype. Based on the analysis, simulation and experimental results, the comparison also presented for future reference.