Grid system pdf

To learn more, view our Privacy Policy. To browse Academia. Log in with Facebook Log in with Google. Remember me on this computer. Enter the email address you signed up with and we'll email you a reset link. Need an account? Click here to sign up. Download Free PDF. A short summary of this paper. The focus of this paper Accepted Nov 8, work is to introduce and analyze a novel fast MPPT strategy applied in an improved grid-connected Residential PV system respecting the current legislative framework in Keywords: Morocco, which allow to the consumer being an actor in the energy transition Maximum power point towards a low-carbon society by reducing his dependence to the electrical grid and tracking managing his own energy consumption efficiently by a good switching between photo- Photovoltaic system voltaic PV source and the grid and therefore making a framework of smart residence Power factor correction management system.

The overall system is designed to improve the energy control Predictive current control performance with two techniques: the first one uses a novel high performance con- troller to track the maximum power point MPP of a photovoltaic array under fast irradiation and load changes. Among the advantages of this proposed controller is the stability of its output voltage with fast response speed to the required parameters.

The second one uses a Power Factor Correction PFC circuit to ensure the power quality regulation in the grid side via a predictive current control method. Finally, the stability of a closed-loop system is simulated and analyzed using commercial software offering sufficient condi- tions to validate a practical stability and robustness of the proposed overall designed system.

In order to confront this challenge, the government has embarked on series of strategies and policies to preserve the exhaustion of its finite natural resources to build a sustainable economy and ensure access to affordable, reliable, sustainable and modern energy for human well-being.

This accelerated consumption trend can only be met by increasing supply and controlling energy con- sumption, Morocco has taken therefore a global leadership position on climate change mitigation by setting different acts and law of energy efficiency and renewable energy for different sectors and especially for build- ing sector [3] such as: Law of November relating to energy efficiency in residential and commercial buildings.

It introduces energy performance ratings for buildings, equipment and appliances. The decree no of November is about the Thermal Regulation for Construction in Morocco TRCM aiming to optimize heating and cooling necessities in new building by improving the thermal performances of the envelope while improving thermal comfort and reducing the energy consumption.

These laws, along with a number of other provisions, are the crucial first steps in the process. The geographical location of Morocco promotes the use of distributed renewable energy systems especially photovoltaic source, that requires further liberalization, particularly increased access to LV network.

Then within the implementation framework for the photovoltaic energy development, the law No amending and supplementing law No on renewable energy was adopted on December For the opening up of the LV network to decentralized producers, the implementing Decree is still being prepared and until this time, no date had yet been fixed for these provi- sions to become effective.

With the existing Moroccan regulatory conditions, the individual producer is not allowed to inject excess power produced from his renewable source system in the LV network and cannot become a share- holder in the energy sector by selling surplus production to the grid operator neither can intrinsically reduce his dependence on power generation plants.

In the literature, most issues carried out about building integrated photovoltaic PV system with bidirectional power flow capability based on inverter circuit for grid synchro- nization control adding to the maximum power point tracking MPPT functions [4, 5, 6] and the impact of interconnecting PV to grid regarding the standardized power quality, the power grid stability and the safety of equipment [7].

This paper examine an improved model designed for grid connected PV, respecting the actual Moroccan regulatory requirements by keeping only one direction power flow, starting from generator source to households appliances based on a proposed novel Maximum Power Point Tracking MPPT technique with higher speed response and stable output voltage waveform of photovoltaic PV systems as well as a good load follower.

The overall system configuration is designed and analyzed using time scale domain simulation of electrical characteristics, showing the stability of DC link output voltage and load power. Due to the fact that PV array efficiency mainly depends on irradiance and temperature [8], so that the required voltage and current are not fed to the loads every time, therefore the LV grid cover the power difference between load and PV, followed by a single phase diode bridge rectifier, providing constant and one way power flow for DC-link, from the grid to the load according to Moroccan regulatory, and then the boost converter controller, which is applied to provide a power factor correction for rectified current waveform.

PV array The output power from a single PV cell is relatively small. So the required electrical energy is pro- duced by grouping the PV cells in series and parallel forming the modules. The PV panels are connected together to build up the entire PV array and any desired current voltage characteristics could be generated [9, 10].

The overall grid connected PV system configuration scheme Figure 2. Maximum power point tracking The maximum power point shown in Figure 2 varies according to the weather conditions. The ba- sic principle of maximum power point tracking MPPT algorithm depends on the exploitation of voltage and current variations caused due to the pulsations of instantaneous power.

In addition, the solar cell exhibits non-linear V-I characteristics as shown in Figure 2 , therefore the MPPT controller must track the maximum power and match the current environmental changes [12]. From the measured voltage and current, the MPPT algorithm generates the optimal duty ratio to maintain the electrical quantities at values corresponding to the desired parameters [14].

There are many MPPT methods available in the literature; the most widely-used techniques are described in [15], the inconvenient of these techniques is the voltage-ripple emerging during attempts to identify maximum power point. For instance, conventional Perturb Observe PO algorithm causes the ripples oscillations even if it reaches maximum power point because of its structure [16]. This difficulty increases the power losses and hardens the control actions.

Hence, some calculation procedures of conventional PO algorithm was modified and the ripples were corrected [17]. The basic circuit diagram of boost converter is shown in Figure 3, it mainly consists of an Inductor L, capacitor C2 , controllable semiconductor switch S, diode D and load. Figure 3. Three columns of four units Two columns of six units Four columns of three units Six columns of two units What should be the size of your columns? Khoi Vinh and Mark Boulton have a nice theory, check their presentation: www.

Think of numbers you can divide by 2 or 3: 72 divided by 2 is 36 72 divided by 3 is 24 72 divided by 4 is 18 50 divided by 2 is 25 50 divided by 3 is You can also think of grid systems based on: Fibonacci numbers: 0, 1, 1, 2, 3, 5, 8, 13, 21, 55, 89, etc Or prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, etc We always want to cram as much information as possible on one page.

Especially vertical space is scarce, often you have to scroll so you never get to see the whole page, or a brilliantly designed page as a whole The amount and type of information text, movies, images are for dynamic websites hard to control.

On with the fancy stuff How to make it movie look good? This building looks rock solid, very well structured. Play with the grid system movie Consider it as a playground instead of a jail Use the grid as a basis, and play with the elements: text, lines, images etc. A very simple and rigid grid. Note that the architect is playing with space, not with the grid itself. Imagine if the extensions are not there, that would be quite a mediocre building right?

As you have seen, what the architect does, is playing with space, by adding or removing it For graphic or visual design this works as well.

The space around the vase forms a silhouette. What the negative space does is defining a shape. There is no negative or white space in this example Nearly every square inch is filled with text or images.

Some websites need every inch of space to get all the information on it Would white space matter for this website? Which one is better? This is a perfect example of how to play with a grid system Note that the guidelines are not centered and how the image is perfectly integrated with the typography All the texts are perfectly aligned to the baseline grid A good grid systems provides solutions to several levels of complexity A good grid system is robust and versatile A grid solves many design problems common and uncommon A good grid is sustainable A genuine classic 1st edition is from Grid systems Kimberly Elam Websites about grids www.

The grid system is an aid, not a guarantee. Bas Leurs. Liz Rose Dec. They know how to do an amazing essay, research papers or dissertations. AshleyGates14 May. While the load typically varies with unknown way because of the vari- ability of residents activities [18]. If it is not higher than the maximum output current, the predicted reference current Iref that the PV controller will track will be equal to the load current value ILoad.

Then, the predicted reference voltage Vref can be calculated from a predicted reference current Iref as given in the equation 2 and will increase or decrease the PWM duty cycle ratio D of the switching device. Figure 4. Predictive control algorithm. Grid connected to DC-link utility conversion The single-phase diode bridge rectifier used in the proposed configuration is widely used in low volt- age distribution systems. However, this classical converter draw non-sinusoidal ac input currents, leading to low power factors and injection of current harmonics into the utility lines [19].

Therefore, it is essential to predict the current harmonic levels produced by these converters [20] by associating them with Power Fac- tor Correction PFC stage based on boost topology with a high switching frequency power conversion. The current control techniques have gained importance in AC-DC conversion used for high performance utilizations, where the fast response and high efficiency are important.

Various current control methods have been proposed in PFC circuits, the most commonly studied are : linear control [21], hysteresis control [22] and predictive control [23], a comparative study given by [24] shows that the predictive control offers a good performances regarding to the others proposed control methods in terms of input current harmonic content and power quality. Therefore this technique makes an extremely attractive choice for our proposed model. The circuit scheme considered in the paper work is illustrated in Figure 5.

Figure 5. Boost converter with predictive control. As it will be shown in simulation results, this technique makes it possible to obtain good performances such as the stability of the system, precise behavior of the currents, input and output voltage.

On the right side of the system scheme, the V AC source provided from single phase grid ensure local supply continuity when there is a lack of irradiation, the delivered power is converted and stepped up to V DC via diode bridge rectifier associated to the boost converter with a PFC controller.

The specifications and the components used in the proposed design are illustrated in Table 2: A novel fast MPPT strategy used for grid-connected residential PV system The overall grid connected PV system scheme. Table 2. And also the PFC converter performances in forcing the input current to follow the wave shape of the rectified input voltage added to the automatic switching between grid and PV for providing stable power to the loads when the environmental conditions are changing.

Therefore; the system is analyzed for different scenarios considering irradiation and load changes: 4. Overall grid connected system operating with full-load and irradiation change The controllers capability is tested with a full residential load under solar irradiation change condi- tions.

Once the system reached its steady state, it proves the stability and the velocity of the proposed MPPT strategy. With the same conditions mentioned above; the DC-link system simulation results with the proposed MPPT controller are shown in Figure 8. This voltage value ensures the good switching between AC grid and PV panel in providing stable power to residential load.

Output voltage, current and power in DC link for full-load In another hand, from the PFC performances shown in Figure 9, the load is supplied by the AC grid because of the low irradiation level and the resulting waveforms shows that the rectified current follows the rectified voltage wave shape and are in phase, which, explain the good tracking capabilities of the Predictive Current Control method when the irradiation conditions change quickly to the optimal condition of sun irra- diation.

The device find the maximum power point of the PV panel then the rectified grid current tends to be zero, explaining that in this duration, the electrical grid becomes idle and the power source is switched to the PV generator. Rectified voltage and current waveforms. Overall grid connected system operating with partial load considering optimal irradiation condi- tion As illustrated by Figure 4 in the previous paragraph, the proposed MPPT controller complies with both full load and partial load.

Therefore,the MPPT controller will adjust the duty cycle of the converter to meet the required load at constant output voltage, then the PV automatically becomes a load follower and operate at the point where the output power matches the load, in this example the output power is close to W. Figure This paper has presented the mod- eling and control design of two-stage: PV system based on a boost converter with the proposition of a novel MPPT technique, with a constant PV output voltage based on predictive control method, to track even the MPP of a PV or another operating point depending on load change and a single-phase grid connected diode rectifier with PFC controller for regulating the DC link voltage and the rectified current waveform with a good track of the reference.

The two stages are connected to a residential load and depending on meteorological conditions they ensure a good switching between them in providing power supplying load. Based on the above analysis of the simulation results, the controllers designed in each stage of this paper offers good performances in term of speed of convergence to the required operating voltage and current parameters added the stability of their waveforms under various atmospheric and operating conditions with minimum tracking time.

Hence, this de- signed system can promote the development of distributed photovoltaic power generation in Morocco and the residential user can forecast his electrical energy consumption and therefore reduce his electrical bill and be an actor in saving the environment.

As a future work, controlling the use of households will be proposed in order to use efficiently the PV generator when we have favorable meteorological conditions by exploiting the Maximum Power Tracking, and use only necessary loads at night. To enhance the reliability and stability of DC-link voltage, the battery system can be added to this model in order to maintain the DC link voltage when occurs a power grid outages. Limsakul, R. Songprakorp, A. Sangswang and P. Chouder, S. Silvestre, N.