Comparative Study on Schemes for Generating Multiple Frequencies with Single Inverter

In wireless charging devices, using single inverter to output multiple frequencies can effectively reduce device size and address the frequency incompatibility problem caused by different wireless charging standards. In addition, in the field of consumer electronics, the demand for simultaneous wireless power supply to multiple receivers is becoming increasingly urgent. Receivers that follow different standards require different transmission frequencies, and the generation of multi-frequency signals from single inverter is becoming an indispensable technology. Two methods for generating multi-frequency signals using single inverter, including multi-frequency programmed harmonic modulation (MF-PHM) and multi-frequency multi-amplitude (MFMA) superposition modulation, are investigated. The two methods are compared from the perspectives of system DC voltage utilization rate and inverter output harmonic components. The advantages and disadvantages of each method, together with the underlying mechanisms, are analyzed. Taking the simultaneous generation of 129.5 kHz, 203.5 kHz, and 351.5 kHz by single inverter as an example, a simulation and experimental platform is established to verify the analysis and conclusions. References and guidance for selecting multi-frequency-generation methods using single inverter are provided.