Wireless charging, as the name suggests, is a technology that allows power to be transferred without the need for physical cables. Unlike traditional charging methods where a cable connects the device to a power source, wireless charging simply requires placing the device on a charging pad. As illustrated in Figure 1, this process involves an alternating current flowing through a coil in the charger (the power output side), which generates a magnetic field. This magnetic field then interacts with a coil in the smartphone (the power receiving side), inducing a current that charges the device. This principle is based on electromagnetic induction.
Despite its convenience, wireless charging faces several challenges. First, interference is a concern. When a phone is placed near other devices like a computer or TV, it can cause disturbances. The question arises: could a wireless charger interfere with household appliances? Second, efficiency remains an issue. Current wireless chargers typically achieve a maximum efficiency of around 85%, which is significantly lower than wired charging. This inefficiency leads to energy waste and room for improvement. Third, cost is another barrier. Wireless charging systems include components such as power management modules, transmitting and receiving circuits, and require patent licensing, making them more expensive than traditional chargers. Fourth, there are limitations in coverage. The charging pad and receiver must be close for effective charging, otherwise the efficiency drops dramatically. Lastly, radiation concerns persist. While wireless chargers generate magnetic fields, they generally operate at low power levels, making safety issues less of a concern compared to high-frequency sources.
Noise problems also arise during wireless charging. As shown in Figure 2, the noise emitted into the environment increases in the low-frequency range below 100 MHz. This can affect television or audio playback, leading to degraded sensitivity and communication issues. During charging, single-segment playback may not receive signals, and incoming calls or messages might be missed.
The noise interference mechanism in wireless charging originates from a frequency converter operating at approximately 100 kHz. Harmonic components around 1 GHz can cause various noise problems. Additionally, noise radiated from the power line and the smartphone’s coil can suppress receiving sensitivity.
To mitigate these noise issues, countermeasures such as inserting a common-mode choke (CMCC) at the power line’s bottom can reduce radiation by about 20 dB. Adding a low ESL capacitor and a common-mode choke before the power output coil can improve reception sensitivity by up to 13 dB, nearly matching the performance when the battery is not being charged.
The technology behind wireless charging is simple in principle but complex in execution. In the early stages, many methods were explored, but only coil induction has reached mass production. This method, discovered over a century ago, was initially used in transformers. However, the challenge lies in maintaining efficient power transfer over distance. Early electric toothbrushes demonstrated that increasing the frequency allows for greater transmission distances, as higher frequencies experience less energy loss.
RFID technology later influenced wireless charging, using low, high, and ultra-high frequencies as reference points. Although wireless charging for electric toothbrushes existed 10 years ago, it lacked sufficient power for modern devices. Recent advancements in resonance technology have improved efficiency, allowing for better power transfer even when the distance between the transmitter and receiver increases.
However, commercializing wireless charging remains challenging. Precise tuning is required for optimal performance, similar to adjusting a piano. Mass production becomes difficult if each product needs individual calibration. Designing self-adjusting systems is crucial for scalability.
In 2008, Intel demonstrated wireless power transmission over one meter, but commercialization lagged due to safety and practicality concerns. High-frequency electromagnetic waves can heat metal objects, posing risks. Safety mechanisms, such as target recognition, are essential to prevent unintended power transmission.
Three key performance indicators—efficiency, safety, and power—are critical for wireless charging systems. Modern systems use resonant designs with components like frequency generators, switching power transistors, coils, rectifiers, and filters. Advanced materials and components enhance efficiency, but the most challenging aspect is ensuring safety. Systems must detect the presence of the correct device before initiating power transfer to avoid hazards.
A variable power system requires a data transmission mechanism to support different devices with varying power needs. This necessitates communication between the transmitter and receiver, making data transmission via inductive coils a key research focus.
While a universal standard for wireless charging would be ideal, achieving it is difficult. It requires common resonant frequencies and standardized data codes. Despite ongoing efforts, market adoption remains limited due to incomplete standards and patent-related costs.
Three key components—control circuit boards, induction coils, and magnetic materials—form the backbone of wireless charging products. As the market grows, it will impact multiple industries, including electronics, mechanical engineering, and chemical manufacturing. This emerging technology presents new opportunities for innovation and development across various sectors.
Uninterruptible Power Supply Battery
This innovative and technological solution promises to provide uninterrupted power supply to your electronic devices, right when you need it the most. Designed to meet your everyday power requirements, our UPS battery is an essential accessory for your home or work place. The Uninterruptible Power Supply Battery is built with advanced technology, ensuring maximum efficiency and performance. Boasting a powerful battery capacity, it is capable of providing uninterrupted power backup for multiple devices such as computers, routers, gaming consoles, and IoT devices. It is a reliable and durable solution that can offer protection against voltage fluctuations, power surges, and outages.
Battery Backups,Battery Back Up Power,UPS Battery Backup,Uninterruptible Power Supply Battery Systems
JIANGMEN RONDA LITHIUM BATTERY CO., LTD. , https://www.ronda-battery.com