Sol Moon

A Fast PV Power Tracking Control Algorithm With Reduced Power Mode

This paper presents a fast maximum power point tracking (MPPT) control algorithm for the photovoltaic (PV) in a hybrid wind-PV system, in which the PV generatormay also need to work in a reduced power mode (RPM) to avoid dynamic overloading. The two control modes, MPPT and RPM, are inherently compatible and can be readily implemented, without the need of a dumping load for the RPM. Following the establishment of a dynamic system model, the study develops the guidelines to determine the variables of a direct hill-climbing method for MPPT: the perturbation time intervals and the magnitudes of the applied perturbations. These results are then used to optimally set up a variable-step size incremental conductance (VSIC) algorithm along with adaptive RPM control. The power tracking performance and power limiting capability are verified by simulation and experiment.

A New Low-Cost Centralized MPPT Controller System for Multiply Distributed Photovoltaic Power Conditioning Modules

In this paper, an integrated maximum power point tracking (MPPT) controller system using a ZigBee wireless communication module is proposed for multimodal power converters as a concept of an intelligent photovoltaic (PV) module of PV power conditioning systems. The proposed scheme can integrate all information under a single host controller to realize low-cost manufacturing. It can also simplify the monitoring and supervision processes through machine-to-machine communications for the smart-grid. The voltage and current information for each module are periodically sampled and transferred to the central inverter (or another host server) through the ZigBee module. After the transmission process, the MPPT control algorithm derives each of the PV voltage reference parameters to return to each PV module accordingly. The technical benefits of the proposed approach is the configuration of a PV-controller system composed of a single digital-signal processor (DSP), low-cost analog controllers, and some mandatory communication peripherals used to monitor the distributed multimodules. Also, the method is quite desirable for supervision and monitoring of the overall system due to its centralized control structure. For the experimental validation of the proposed MPPT control, multiple ZigBee (XBee-PRO series) modules, as well as a DSP, dual-module solar simulators, and a couple of 50 W dc-dc power conversion hardware prototypes were utilized.

Series-connected isolated-switched-capacitor boost converter

This paper proposes novel high-step-up DC-DC converter using an isolated switched capacitor cell. The proposed converter uses the coupled-inductor, coaxial cable transformer, and switched-capacitor techniques. The output of the boost converter and isolated switched-capacitor cell are connected in series for high-step-up with a low turn-on ratio. A prototype circuit with 30-40V input voltage, 340V output voltage and 150W output power is implemented in the laboratory to verify the performance of the proposed converter.

Stand-alone operation with a centralized controller for multiple PV module converters

In this paper, stand-alone control with Maximum Power Point Tracking (MPPT) control and output voltage of converter control method using Zigbee wireless communication for multiple module converters is proposed as a concept of the intelligent PV module of the photovoltaic power conditioning systems (PCS). The proposed scheme integrates all the information for a single host controller to choose which one of the entire PCS group regulates the output dc-link voltage of the converters or regulates the input voltage for the MPPT control under stand-alone condition. Individual modules voltage and current information is periodically sampled and transferred to Zigbee module of a centralized inverter. Then, the information is delivered to the main controller through SCI (Serial Communication Interface) operation. After the transmission process, the central Digital-Signal Processor (DSP) operates the MPPT control and the output voltage regulation for each converter. In grid connected condition, every module performs the MPPT for its own PV panel. The technical benefits of the proposed approach are its flexibility to handle the blackout or sudden disconnection of grid. Also it can decrease the material cost and simplify the monitoring and supervising process through Machine-to-machine (M2M) cloud infrastructure for smart-grid test-bed. Also the method can communicate with other equipment or home appliance under the M2M cloud infrastructure. For the experimental validation of the proposed stand-alone control, multiple Zigbee wireless communication module, as well as a DSP, dual-module solar simulator, and couple of boost converter prototype are utilized.

Photovoltaic maximum power point tracking without current sensor for module integrated converter

In this paper, a simple maximum power point tracking (MPPT) method for series-connected DC-DC converter module of photovoltaic power conditioning systems (PCS) is proposed. This approach enables maximum power point (MPP) tracking control with the converters output voltage information instead of calculating solar array power, which significantly simplifies the sensor network by removing current sensor. Furthermore, there is no multiplication process in the P&O algorithm to track the maximum power point because the power calculation is replaced by output voltage sensing. This simple MPPT control strategy can reduce the cost and size, and can be utilized with a low performance / low cost controller. For verification of the proposed control strategy, Zigbee (Xbee-pro) wireless communications and DSPs Series Communications Interface are utilized. Also series-connected hardware prototype with multiple photovoltaic modules was built and tested.

High efficiency step-down flyback converter using coaxial cable transformer

This paper proposes step-down flyback converter using coaxial cable transformer which has higher coupling than sandwich winding transformer. Proposed transformer converter has higher efficiency than conventional in same condition. The structure of the coaxial cable transformer is described and the results of the coupling of coaxial cable transformer and sandwich winding transformer are compared. Finally, performance of the proposed transformer is validated by the experimental results from a 35W single-output prototype and 35W multi-output prototype.

Single MPPT controller for multi-module converters using wireless communication

Module integrated converter (MIC) has great flexibility and efficient energy harvesting capability. But, according to the increases of PV module, the cost of implementation also increases. In this paper, in order to simplify the function of each module, single remote digital MPPT controller is proposed. Sampled parameters of PV voltage and the current of each module are transmitted to digital controller (TMS320F28335) in the central inverter or in a gateway. Then, a voltage reference is sent back to each module by Zigbee wireless communication. The reference voltage is determined by perturbation and observation MPPT algorithm (P&O). To evaluate the proposed MPPT method, a couple of 50W Module Integrated Converter and several Zigbee transceiver for wireless communication module were utilized.

High Power DC?DC Conversion Applications of Disk-Type Radial Mode Pb(Zr,Ti)O3 Ceramic Transducer

In this paper, a new application of magnetic-less high-power DC–DC switching converter with an Pb(Zr,Ti)O3 Ceramic transducer is described. For the full elimination of magnetic devices from the high power application, this paper presents a resonant-type step-down DC–DC power converter employing a disk-type piezoelectric transducer, along with the demonstration of the design process and the hardware-experiment results. For validation of the feasibility, a 10 W output DC–DC power converter hardware was implemented. The experimental result shows an excellent output control capability under switching frequency variation with a high power-efficiency greater than 95%. The thermal distribution image of the transducer under the high power operation was also measured. The result shows that the transducer has very stable thermal operation even under the full load condition.