The role of coils in wireless chargers: Wireless chargers are devices that use the principle of electromagnetic wave induction for charging, similar to a transformer. There is a coil at both the transmitting and receiving ends. The transmitting coil is connected to a wired power source and generates an electromagnetic signal. The receiving coil senses this electromagnetic signal and generates current to charge the battery. During system operation, the input terminal converts AC mains power to DC power through a full-bridge rectifier circuit, or directly uses a 24V DC power supply. The output DC power, after passing through a power processing module, is converted into high-frequency AC power by a 2MHz active crystal oscillator inverter, supplying the primary winding. Through the coupling energy of the two induction coils, the receiving conversion circuit converts the current output from the secondary coil into DC power to charge the battery.
Inductor's throttling effect: The self-induced electromotive force in an inductor always reacts against changes in the current within the coil. An inductor impedes alternating current; the magnitude of this impediment is called inductive reactance xl, measured in ohms. Its relationship with inductance l and alternating current frequency f is xl = 2πfl. Inductors can be mainly classified as high-frequency throttling coils and low-frequency throttling coils. Tuning and frequency selection: An inductor connected in parallel with a capacitor forms an LC resonant circuit. When the circuit's natural oscillation frequency f0 is equal to the frequency f of the non-AC signal, the inductive reactance and capacitive reactance are also equal. Electromagnetic energy then oscillates back and forth between the inductor and capacitor, resulting in the resonance phenomenon of the LC circuit. At resonance, the inductive reactance and capacitive reactance are equal in magnitude but opposite in direction. The total current in the circuit is at its minimum inductive reactance and maximum current (for AC signals where f = f0). The LC resonant circuit has the function of selecting a frequency, allowing it to select an AC signal of a specific frequency f.
Wireless charging coils are commonly used as current transformers, offering wide bandwidth, small size, light weight, and ease of digital measurement, as well as protection for microcomputers. They are widely used in television and audio manufacturing, communication transmission and reception, power filtering, VCD RF heads, antenna amplifiers, tape recorders, and antenna microphones. Wireless charging coils are frequently seen in our lives, and with increasingly advanced technology, their applications are expanding. Self-adhesive coils are widely used in common-mode filters, multi-frequency transformers, impedance transformers, balanced and unbalanced conversion transformers, EMI noise suppression in electronic devices, USB lines in personal computers and peripherals, LCD panels, low-voltage differential signals, and car remote keys. As the electronics industry has developed, wireless charging coils, as a small but vital component, play a significant role and are an indispensable part of many products. For example, induction cookers cannot effectively preserve the color, aroma, flavor, and nutrients of food without a coil. Therefore, this small component is essential for modernizing the kitchen.
Coupling energy charges the battery. Key features of wireless chargers: 1. Theoretically, wireless charging technology is safe and harmless to the human body. The resonance principle of wireless charging is magnetic field resonance, which only transmits between resonant coils of the same frequency. Other devices cannot receive the waveband. Furthermore, the magnetic field used in wireless charging technology is harmless to the human body. However, wireless charging technology is still a relatively new technology. Jinhaode Inductor's wireless charging coils feature: 1. Multi-core stranding, high power, strong heat dissipation, and low heating; 2. High structural flexibility and easy installation; 3. Magnetic field convergence, improving electromagnetic efficiency. Conversion rate has always been a concern. MIT found that wireless charging technology consumes more energy than wired charging technology. Jinhaode Inductor's wireless charging coils have a conversion rate several percentage points higher than wired ones. High conversion rate is also an important factor in the widespread application of wireless charging coils worldwide.
The widespread adoption of wireless charging technology can be attributed to the rapid development of the electric vehicle industry. Wired charging stations for electric vehicles have long been plagued by problems such as large footprint, complex operation, and high wear and tear. Inductive wireless charging technology has been successfully applied to some electric vehicle charging systems. The transmitting system is buried underground, while the receiving coil is typically located in the vehicle chassis. The transmitting and receiving coils are inductively coupled, acting like a separable transformer, and wirelessly transmitting electrical energy through the high-frequency electromagnetic field between the coils. To improve system efficiency, the first step is to accurately measure the power of each component. Power analysis is essential for this. However, commonly available power analyzers face several challenges when measuring wireless charging systems. Failure to address any of these issues can lead to inaccurate power measurements or even results in efficiencies exceeding 100%.
