E2WATT is a new patented wireless power hybrid technology created by Eggtronic, intended to increase power and efficiency in wireless charging applications for home appliances and the automotive field. In an interview with EE Times, Igor Spinella, CEO and founder of Eggtronic, noted that the technology is powered by a GaN half-bridge and a dsPIC33 microcontroller, and integrates a conventional transducer and a Qi wireless transmitter, ensuring enhanced efficiency to overcome the difficulties of the Qi standard. Traditional Qi wireless power is limited by distance (usually 5mm), and maximum power (usually up to 30W). Another aspect to consider with the Qi standard is overheating: after some time in fast charging, the thermal protection is activated, which stops charging. “Our solutions direct the magnetic field in the right way, avoiding the problem of overheating not only for the Qi standard, but also providing compatibility with the new Apple 12, which is not Qi-certified, paving the way not only for cars but also for consumer applications,” Igor Spinella noted. Spinella notes that the new hybrid technology with AC input does not require an AC/DC converter and allows up to 95% efficiency with powers up to 300W and a 40mm pitch while reducing overall size thanks to GaN support.” Capabilities can be increased, reproduced scalability The app is for large scale applications such as charging electric vehicles. 95% was achieved at a distance of 10mm, which is twice what we can achieve with the Qi standard, which at 5mm is usually no more than 70%, which is a real breakthrough for induction standards.” The Qi Standard The Qi wireless power transmission system consists of two basic modules , namely the base station and the portable device, as shown in Figure 1. The base station includes one or more power transmitters capable of providing wireless power transmission and consists in principle of a power conversion unit, a control unit and a communications unit. Responsible for driving a coil called the primary coil, and the digital features responsible for controlling the process of power transmission and communication with other parts of the system Figure 1: A typical wireless charging system uses magnetic coupling between a primary coil in the transmitter and a secondary coil in the receiver to transmit power and exchange data ( Source: STMicroelectronics) The mobile device includes one power receiver which in turn consists of an energy harvesting unit, a control unit and a communication unit.At the same level as the transmitter, we have a subsystem of an analog nature and another digital system to improve the operation. The actual power transfer from the base station to the mobile device is obviously achieved by inductive coupling between the primary and secondary coils: once placed in close proximity, these coils create a resonant transformer in the air with resonant frequencies of the order of 100 kHz. This power transfer is also constantly monitored and controlled by the system logic for the changing power requirements imposed by the device itself depending on its current state (for example, the completion of the battery charging process). Currently, this technology allows wireless power transmission of up to 30 W at an operating frequency of 100-200 kHz at a distance of up to 5 mm. E2WATT technology with about 200 patents Founded in 2012, Eggtronic specializes in wireless power and energy conversion. Over the years, it has been able to direct its expertise towards different consumer solutions through inductive and scaling solutions: Eggtronic has already raised more than 20 million in venture capital and it was in the news a few weeks ago that the European Investment Bank (EIB) is considering offering a 15 million loan to companies Eggtronic. “Based on the Qi standard, we already serve several automotive companies. Recently, we decided to increase the level of integration of our solutions in order to launch our own standards capable of increasing performance and features. Thus, we developed our own ASIC, which is entirely designed and built by TSMC,” he said. Spinella. E2WATT is Eggtronic’s latest wireless technology (Fig. 2); It is powered directly from AC mains without the need for an external power source. It is a hybrid wireless AC power solution that is both a wireless power supply and charger. “The goal was to have a product that could be better than an equivalent wired power supply unit. It has been certified as a power source from an emission and safety standpoint, and it is of course a wireless power transmission technology,” Spinella said. E2WATT focuses on Navitas’ GaN technology, thus highlighting the difficulties of silicon to reach certain levels. The problem with silicon is the switching frequency: you’re limited to around 100kHz, and if you try to push it too hard, you’ll get uncontrollable heat, complexity, and costs. Then there are the problems with the low frequency magnets, which are not fast enough, and get too slow when you try to drive that fast. Many people use “static switching” topologies that cause a lot of shunt losses, and when you increase the frequency, the efficiency drops due to increased parasitic inductance. Also, the old topology and legacy control ICs can’t run fast enough. So, the first step is to solve the switching problem – through GaN technology. Navitas’ GaNFast solution consists of a GaN switch – a field-effect transistor (FET) – with monolithic analog drive circuits and digital logic circuits integrated into the same chip as the GaN power device. GaNFast power integrated circuits are rated at 2MHz. High-speed operation provides significant reductions in the volume and cost of power conversion for fast charging systems. In addition to GaN technology, Microchip Technology’s dsPIC33 microcontroller with U core DSP, high-speed ADC, and high-precision PWM digital architecture enables the E2WATT system to offer transmission control with improved charging distance. Spinella noted that thanks to its receiver technology, the platform enables a significant drop in receiver temperatures. Figure 2: E2WATT efficiency (Source: Eggtronic) Figure 3: Cluster diagram of E2WATT technology (Source: Eggtronic) “Figure 3 shows the block diagram of E2WATT. In a transmitter, the logical function is to convert AC power from the network to another AC frequency. To energize the coil.The base then is a semi-bridge circuit by Navitas for LC tank induction, which is common to the Qi standard.The proprietary architecture allows for high direct input voltage, eliminating the need for an AC/DC converter in series, and for zero voltage switching (ZVS). ) without the use of a resonant LC tank, ensuring plenty of ZVS is achieved in each load condition, allowing continuous control from light load to full load, without the use of burst mode,” Spinella said. ZVS significantly reduces capacitive switching losses when outage and reduces switching losses when switched on. It eliminates capacitive operating loss. It is suitable for high frequency operation. On the secondary side, Spinella highlighted that the receiver functions as a rectifier and as a non-dispersive regulator; This is achieved by controlling the ratio between the active power delivered to the load and the reactive power reflected on the primary side. “The reactive power in the wireless system (transmitter and receiver) is reduced thanks to a second control loop that ensures minimal reactive power in the system,” Spinella said. Wireless charging is faster, easier and undoubtedly more convenient than the wired alternative. However, it is worth considering not only efficiency but also thermal performance, which most developers consider a secondary design consideration in order to bring their products to market faster. Electric vehicles are large energy stores, and the ability to provide more energy with less frequent charging is a short-term goal to support the emergence of electric vehicles. The larger the battery, the greater the current flow rate and heat generation. Incorporating technology into electric cars and strategically installing charging pads around cities and in owners’ homes may eliminate the need to deliver vehicles for charging to some extent. .
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