The market for high-powered self-charging solutions is rapidly expanding, and Wibotic has announced its latest developments in tabletop battery chargers as well as wireless charging transmitters for drones and autonomous mobile robots using GaN technology. By utilizing GaN technology and ensuring survivability under the most severe working conditions, innovative solutions deliver higher efficiency. It also enables operators to track and improve the performance of individual batteries, as well as to design charging procedures fully automated or manual, when used with WiBotic software. Adaptive matching technology is able to deliver the power levels needed for drones and other flying devices, thanks to an advanced inductive power transfer mechanism, and among the new WiBotic products are a passive-cooled onboard charger and a fully sealed IP67 charger. As do two smaller, more efficient transmitters that use the latest gallium nitride (GaN) technology from GaN systems, according to Ben Waters, CEO of WiBotic. In an interview with EEWeb, Waters said: “GaN has allowed for significant savings in transmitter size, temperature, and efficiency. The extremely low gate capacitance in a GAN FET allows for much less power required to drive the gate compared to a MOSFET, thus improving efficiency and reducing size.” The switching loss at higher frequencies is also lower compared to conventional MOSFETs, resulting in improved temperature performance.” GaN Technology The main advantage of GaN is its higher energy density compared to silicon. This is due to the presence of the conduction and valence bands gap which is higher than that of LDMOS techniques, providing a larger breakdown voltage. The high power density allows the signal to be transmitted over large distances, which expands the coverage area of base stations. It also enables smaller form factors that require less space on the PCB. Thus designers can get more power in a smaller space, which in turn reduces costs. “We have primarily used GaN in our transmitter up to this point. GaN may be useful in other products, such as standalone desktop battery chargers where we can improve the efficiency and reduce the size of our DC-DC switching converters. For UAV applications, for example, Size and weight are essential to any onboard charger,” Waters said. Gallium nitride has a band gap of 3.2 electron volts (eV), nearly three times higher than silicon, which is 1.1 eV. This means that more energy is required to excite the valence electron in the conducting band of the semiconductor. While this property limits the use of gallium in very low voltage applications, it has the advantage of allowing greater breakdown voltages and greater thermal stability at higher temperatures. GaN significantly increases the efficiency of power conversion phases, serving as a valuable substitute for silicon in the production of high-efficiency voltage transformers. Wibotic’s Systems WiBotic technology has evolved to include both tabletop battery chargers and fully independent wireless chargers, all of which are not attached to the battery, can be networked and monitored remotely through the WiBotic Commander software. With the onboard WiBotic chargers, any type of battery can be charged manually from a DC power source. The onboard chargers can also be used to charge devices independently using wireless charging. WiBotic wireless charging technology builds on the strengths of both inductive and resonant systems because it combines the best of both. The patented Adaptive Matching system constantly monitors the relative antenna position and dynamically adjusts hardware and firmware parameters to maintain maximum efficiency – delivering reliable charging, at high power levels, and across several centimeters of vertical, horizontal and angular displacement. WiBotic wireless charging systems consist of four basic hardware components: the transmitting unit, the transmitter antenna coil, the onboard charging unit, and the receiving antenna coil. The transmitter recognizes any incoming robot with an onboard charging unit and receiving antenna coil and activates automatically to provide the right amount of power. The collector coil supplies power to the onboard charger circuit. The onboard charger converts the signal back to DC voltage and controls battery charging functions to safely charge a wide range of batteries. Figure 1: How WiBotic Wireless Power Solutions Work (Source: Wibotic) The OC-262 is a passively cooled internal charger developed as a rugged system for commercial and government applications. Passive cooling is particularly useful in harsh environments such as mining, offshore exploration, and agriculture where water and dust are a major concern. The OC-262 consists of two models, one with an IP20 rating for applications that require passive cooling but may be more open to the environment, and one with an IP67 rating for use in outdoor or harsh environments. “The OC262 is the first onboard charger to be passively cooled. For outdoor applications in particular, the ability to completely shut off electronics is something we’re hearing from many customers. The OC262 addresses this need. Passive cooling mitigates the need for ventilation,” says Waters. External to any device, robot, drone, space, etc.” Figure 2: Wibotic transmitters Figure 3: Onboard Wibotic chargers Another solution is the onboard charger OC-150 for smaller robots that Delivers up to 150W of total power and up to 10A of current depending on battery voltage.In the field of transmitters, the TR-150 uses the latest high-efficiency GaN transistors from WiBotic partner GaN Systems Inc., and is primarily designed for use with the charger The new onboard OC-150 but supports all WiBotic OCs when deployed in diverse robot fleets.The TR-300 transmitter offers the same basic features as the TR-150 but delivers up to 300W of power when paired with WiBotic’s OC-262 chargers. or OC-301 on board.” This allows IoT connectivity products for an ecosystem of charging and power management products, all connected by WiBotic Commander software. Many companies are still working towards fully automated deployments, and we have products that can help desktop shipping today, and those same products can be applied to fully autonomous shipping as things continue to progress in that direction,” Waters commented.