Review of architectures based on partial power processing for DC-DC applications

This paper presents a review of advanced architectures based on the partial power processing concept, whose main objective is to achieve a reduction of the power processed by the converter. If the power processed by the converter is decreased, the power losses generated by the power converter are reduced, obtaining lower sized converters and higher system efficiencies. Through the review 3 different partial power processing strategies are distinguished: Differential Power Converters, Partial Power Converters and Mixed strategies. Each strategy is subdivided into smaller groups that entail different architectures with their own advantages and disadvantages. Also, due to the lack of agreement that exists in the sources around the naming of the different architectures, this paper seeks to stablish a nomenclature that avoids confusion when indexing this type of architectures. Regarding Partial Power Converters an extensive application oriented description is also developed. Finally, the main conclusions obtained through the review are presented

Partial Power Processing Based Converter for Electric Vehicle Fast Charging Stations

This paper focuses on the design of a charging unit for an electric vehicle fast charging station. With this purpose, in first place, different solutions that exist for fast charging stations are described through a brief introduction. Then, partial power processing architectures are introduced and proposed as attractive strategies to improve the performance of this type of applications. Furthermore, through a series of simulations, it is observed that partial power processing based converters obtain reduced processed power ratio and efficiency results compared to conventional full power converters. So, with the aim of verifying the conclusions obtained through the simulations, two downscaled prototypes are assembled and tested. Finally, it is concluded that, in case galvanic isolation is not required for the charging unit converter, partial power converters are smaller and more efficient alternatives than conventional full power converters

Resonant Dual Active Bridge Partial Power Converter for Electric Vehicle Fast Charging Stations

This paper presents an analysis and design of a DC-DC charging unit for an electric vehicle fast charging station. Due to the benefits that partial power processing achieves in terms of size reduction and efficiency improvement, it is decided to implement a partial power converter architecture. This type of architectures reduce the power to be processed by the converter, but they require an isolated topology. Therefore, a dual active bridge series resonant converter is selected for the study due to its benefits in terms of soft switching conditions. Design wise, it is decided to ensure zero voltage switching at the secondary side of the converter. Indeed, one of the benefits of the implemented partial power converter is the reduced voltage that exists at the primary side. This way, lower voltage overshoots and switching losses are expected. Finally, via simulations, it is confirmed that partial power processing can be achieved with a resonant converter and that zero voltage switching operation is ensured at the secondary side through the entire charging process

Peripheral Interface Controller (PIC) Based Maximum Power Point Tracking (MPPT) Algorithm For Photovoltaic (PV) DC To DC Boost Converter

This report is about to develop of Maximum Power Point Tracking (MPPT) algorithma for photovoltaic (PV) by using Peripheral Interface Controller (PIC). PV Module is a photovoltaic system that uses the photovoltaic array as a source of electrical power supply. Every photovoltaic (PV) array has an optimum operating point, called the maximum power point, which varies depending on PV temperature, the insolation level and array voltage. The function of MPPT is needed to operate the PV array at its maximum power point. The design of a MPPT is proposed utilizing a boost-converter topology. Solar panel voltage and current are continuously monitored by a closed-loop microprocessor based control system, and the duty cycle of the boost converter continuously adjusted to extract maximum power. The design consists of a PV array, DC - DC Boost converters (also known as step-up converters) and a control section that uses the PIC18F4550 microcontroller. Thus, the output voltage from DC-DC boost converter will be boost up approximately to 60V DC output voltage from load and should minimize in ripple voltage and tends to reach constant DC output voltage. Therefore, the conversion of sustainable energy from Photovoltaic (PV) system and step up by DC-DC boost converter circuit will be capable utilize large amount of output voltage. The control section obtains the information from the PV array through microcontroller’s Analog to Digital Converter (ADC) ports and hence to perform the pulse width modulation (PWM) to the converter through its Digital to Analog Converter (DAC) ports. Many such algorithms have been proposed. However, one particular algorithm, the constant voltage method, claimed by many in the literature to be inferior to others, continues to be by far the most widely used method in commercial PV MPPT’s. The microcontroller is programmed with a simple and reliable MPPT technique

Power Electronic Architecture for Multi-Vehicle Extreme Fast Charging Stations

Electric vehicles (EV) are quickly gaining popularity but limited driving range and a lack of fast charging infrastructure are preventing widespread use when compared with gas powered vehicles. This gave rise to the concept of multi-vehicle extreme fast charging (XFC) stations. Extreme fast charging imposes challenges in the forms of power delivery, battery management, and energy dispatch. The extreme load demand must be handled in such a way that users may receive a timely charge with minimal impacts on the electric grid. Power electronics are implemented to address these challenges with highly power dense and efficient solutions. This work explores a power electronic architecture as one such solution. The system consists of three parts: a cascaded H-bridge (CHB) active rectifier that interfaces to a medium voltage (MV) grid, a dual active bridge (DAB) based solid state transformer (SST) that provides isolation and forms a low voltage DC (LVDC) bus, and full bridge DC-DC converters configured as partial power converters (PPC) that interface with the vehicle battery

Partial Power Processing Based Charging Unit for Electric Vehicle Extreme Fast Charging Stations

This paper presents an analysis and design of a charging unit inside an electric vehicle extreme fast charging station. Due to the benefits that partial power processing achieves in terms of size reduction and efficiency improvement, it is decided to implement a partial power converter architecture. This type of architectures reduce the power to process by the converter but, they require an isolated topology. Therefore, a dual active bridge is selected for the study. Then, design wise, four different turns ratio values are selected and their performance results are compared in terms of processed power by the converter, semiconductors stress factor and energy loss. Finally, it is concluded that the turns ratio value is a key factor that must be correctly selected for optimizing the concerned comparison parameters

Dynamic performance comparison of DFIG and FCWECS during grid faults

Among several types, variable speed-based wind turbine generator (WTG) is the most popular type installed worldwide. This type of WTG is able to extract 5% more energy from wind speed compared to the fixed speed WTG. There are two kinds of variable speed based WTG; Doubly Fed Induction Generator (DFIG) and Full Converter Wind Energy Conversion System (FCWECS). DFIG and FCWECS are placed at the first and second topWTG installation worldwide since 2004. However, both of them are very sensitive to the grid dip fault and may violate the allowable margins identified by various international Fault Ride Through (FRT) codes. This paper aims to investigate the responses of DFIG and FCWECS during certain level of grid dips and compare their performanceunder such event. Results show some differences of the performance of DFIG and FCWECS during voltage sag event, however the voltage profile at the point of common coupling is much better in case of DFIG. Results also recommend that DFIG can be effective when connected to weak grids whilst FCWECS is preferably to be connected to strong grids

Bidirectional partial power converter interface for energy storage systems to provide peak shaving in grid-tied PV plants

The ever growing participation of modern renewable resources in electric markets has shaken the paradigm of generation-demand constant match. Most modern renewables add intermittent behaviour and high variability to electric markets, forcing other renewables and themselves to perform power curtailment and/or having extra generating units connected to the network to compensate power, voltage and frequency variations. In order to handle this scenario, Energy Storage Systems (ESSs) have risen as enabling technologies capable to provide backup energy to compensate power, voltage and frequency fluctuations and, at the same time, offer additional benefits as ancillary services, peak shaving, load shifting, base load generation, etc. This paper presents a novel bidirectional Partial Power Converter (PPC), as an interface between a Battery ESS (BESS) and a grid-tied Photovoltaic (PV) plant. To obtain a better understanding of the converter, its mathematical model is presented and its operation modes are explained. The main purpose of this configuration is to provide peak shaving capability to a grid-tied PV plant, while providing a high efficiency BESS. Simulation results show the operation of the full system (grid-tied PV plant and BESS), performing peak shaving under a step-down and up in solar irradiation

A novel modified sine-cosine optimized MPPT algorithm for grid integrated PV system under real operating conditions

This research work presents a modified sine-cosine optimized maximum power point tracking (MPPT) algorithm for grid integration. The developed algorithm provides the maximum power extraction from a photovoltaic (PV) panel and simplified implementation with a benefit of high convergence velocity. Moreover, the performance and ability of the modified sine-cosine optimized (MSCO) algorithm is equated with recent particle swarm optimization and artificial bee colony algorithms for comparative observation. Practical responses is analyzed under steady state, dynamic, and partial shading conditions by using dSPACE real controlling board laboratory scale hardware implementation. The MSCO-based MPPT algorithm always shows fast convergence rate, easy implementation, less computational burden and the accuracy to track the optimal PV power under varying weather conditions. The experimental results provided in this paper clearly show the validation of the proposed algorithm