Pieter Bauwens

New driving scheme for intelligent power‐efficient high‐voltage display drivers

— A new bistable-display driver is presented. The innovation in the developed driver is the addition of a new logical block that calculates the most energy-efficient driving waveforms. In this paper, the algorithms being applied to the row and column waveforms in order to reduce the power consumption are discussed. Some theoretical as well as experimental results are shown, proving a reduction in the power consumption by about 50%. The proposed algorithms are especially important for battery-powered applications.

Improved passive-matrix multiplexability with a modular display and UTCP technology

One of the major problems with PM displays is that, depending on the used display material, only a limited number of lines can be multiplexed. We developed a new driving technology and display setup that takes care of that problem. We divided the display into several independent parts or modules. Each module acts as an individual display and has its own display driver. With the use of the new ultra-thin chip package (UTCP), these driver chips can be embedded into the (flexible) display itself. This paper explains the setup of the fully modular display and describes the basic structure of the display drivers and its components.

Reconfigurable Topologies for Smarter PV Modules: Simulation, Evaluation and Implementation

In a reconfigurable PV panel, the connections between groups of cells (cell-strings) can be rearranged in order to increase the overall power output under non-uniform conditions. In a traditional PV panel, current mismatch between the series-connected cells (due to irradiation differences of differential aging) limits the generated power output by either reducing the overall current or by bypassing the substring containing the limiting cells. A reconfigurable panel can respond to such a situation by changing the connections to a more favorable configuration, allowing the majority of the cells to operate at their MPP. This paper elaborates on such a topology and its components (high current switches, wiring). To get a clearer picture of the added value of such a reconfigurable panel, a detailed energy yield analysis was performed which includes the performance of those added components. The simulation model used for this analysis is calibrated with extensive measurement results. A comparison of that model and corresponding measurements will be discussed. The analysis shows that a reconfigurable PV panel can outperform the traditional panels when suboptimal conditions are predominant, as encountered for instance in BIPV. As a demonstration of the principle, a small-scale prototype was created and will be presented in this paper.

Nimbus: Nmos-Based Integrated Modular Bypass for Use in Solar Systems

Irradiance differences on PV cell level can cause the total output power of a PV panel to drop disproportionally. If no action is taken, a single cell can limit the output current of the entire panel. Traditionally this is solved by placing a bypass diode in parallel to a substring of cells. However, when such a diode is active, it creates a significant voltage drop, and this dissipates power that we would rather see at the output. The SmartPV project, an IWT-SBO project funded by the Flemish Government (Flanders, Belgium), aims at increasing the power yield of PV panels under partial shading conditions. With each of the partners (imec, Ghent University, University of Leuven, VITO) working in different areas, we at Ghent University developed a smart bypass. It takes over the function of a bypass diode, while minimizing the power loss. It is a low-voltage-drop switch that is activated when a failing cell is detected. The NIMBUS chip is a fully integrated smart bypass. The NIMBUS chip is designed for a load current of 5A, while limiting the voltage drop to 100mV. When larger load currents need to be provided, several NIMBUS chips can be placed in parallel. An integrated synchronization circuit ensures that all parallel NIMBUS chips work as one. A prototype of the NIMBUS was created, and the first measurements are presented. Also, the first steps in creating a full module with NIMBUS devices are taken.

P‐42: A New Driver for an Intelligent Modular Display System

Modular displays can be used to build large-scale displays or displays with an irregular shape. With our intelligent modular display system, more complex display structures can be created. The display configuration is completely automatic. The display shape and changes thereof are detected and shown in the User Interface.

Drivers for free‐form modular displays

— When displays of different sizes and shapes are required, a modular display system seems to be a good solution. Many systems offer only a limited freedom of shapes. The display can be scaled, but no irregular shapes can be created. If those shapes can be created, the configuration is often manual. A more intelligent modular system allows all shapes to be created and configures automatically. This paper presents two drivers that can be used in such a modular system. The first driver ensures that the data finds its way to every module and is displayed, even if there are some “holes” in the display due to missing modules. The second driver adds some extra functionality. The precise display configuration can be detected, and in the graphical user interface (used for controlling the display) the user sees an updated view of the display configuration when modules are added or removed. Both drivers have been proven successful and results are presented in this paper.

Integrated switch for substring reconfiguration to optimize module power under partial shading

The output power of a PV module can drop significantly if there is a current mismatch between the series-connected individual cells. This current mismatch can arise due to differences in temperatures of the cells or simply because of partial shading of the PV panel. The most common solution to this problem is by bypassing those limiting cells (in practice, the entire substring containing them is bypassed) and in doing so, ensuring a higher output power. The problem with this approach is that there might still be a lot of power available in those bypassed cells, both in those who are actually shaded (when it is not a 100% shade) and in those still fully illuminated, but merely belonging to that bypassed substring. A reconfigurable module topology might be more efficient. In such a topology the connections between the substrings can be rearranged during operation in order to maximize the module power output. For this topology to be effective, a network of very low-ohmic (not exceeding a few m) switches are needed, capable of communication from anywhere in the panel. This paper describes the design of such a reconfiguration switch.

FrIIDoM: An intelligent driver for automatic configuration in modular display systems

FrIIDoM provides an intelligent solution for automatic configuration in modular display systems. Modular displays are displays that consist of small, identical modules. There are a number of ways they can be used: removing the limitation in multiplexability in passive matrix PM displays, increasing brightness in PMOLED displays, reducing power consumption in bistable displays, creating large-scale displays or displays with variable size and shape. For the modules to work together as one display, some initial configuration is required. FrIIdoM consists of four different drivers, with rising levels of complexity, each with their own way of automating the configuration. The simplest systems just make sure that every module is capable of receiving specific image data, irrespective of the shape of the display. The more complex systems are capable of detecting the presence and location of each module, thus detecting the shape of the display. In the created GUI, the user sees a real-time view of the display configuration, even when modules are added or removed while the display is running. While FrIIDoM is equipped with the drivers to drive a PM LED display, they can be easily changed to incorporate other types of display technologies. Several test modules were created, and we were able to build and successfully drive random display creations. Copyright