| Inductively Power Transfer(IPT)technology based on the principle of electromagnetic induction effectively solves many shortcomings of traditional power transmission through cables.Because of its high transmission power,high efficiency,safe and reliable,simple principle and easy implementation,etc.More and more products supporting wireless charging come into our life.The IPT systems currently in use are mostly based on a single transmitting coil structure.With the in-depth application of IPT technology,its application scenarios are gradually evolving toward high-power fields,such as electric vehicles,household appliances,industrial robots,etc.In the case of providing high power,the inverter unit of the IPT system will withstand greater voltage and current stress,increasing system losses and reducing system reliability.The dual excitation IPT system can effectively increase the transmission power of the system by adding a set of transmitting coils,and has broad application prospects.This paper focuses on the compensation topology,coupling mechanism,and constant voltage output control method of the dual-excitation IPT system under the condition of variable mutual inductance.The aim is to propose a more suitable topology,coupling mechanism and control method for the dual-excitation IPT system.In order to improve the frequency offset characteristics of the system,this paper compares and analyzes the output performance of commonly used topologies.Based on the impedance matching method,this paper designs a harmonic matching calculation method suitable for the primary side LCC topology and the secondary side arbitrary topology structure,based on LCC-S topology structure builds the theoretical model of the dual excitation system,deduces the parameter configuration method and realizes the decoupling of the mutual inductance between the two transmitting coils.Analyze the influence of mutual inductance on the power of two excitation units.In order to improve the reliability of the dual excitation system when the receiving coil is offset.This paper proposes a coupling mechanism based on nested winding.The coupling mechanism can effectively ensure that the mutual inductance generated by the two transmitting coils is basically the same no matter where the receiving coil is located.Solve the problem that when the receiving coil is offset,the mutual inductance between the transmitting coil and the receiving coil increases while the other decreases,Therefore,the two transmitting mechanisms can maintain the same power output,and when the receiving coil is offset,the output current of the two inverters can be automatically shared without any control means,which effectively improves the stability of the dual excitation IPT system.In order to make the system maintain a constant voltage output when the mutual inductance changes,at the same time reduce the volume and weight of the system receiving device,this paper adds control on the primary side,and calculates the mutual inductance by detecting the output current and input voltage of the inverter.The mutual inductance value is processed by the single-chip microcomputer to control the output voltage.This method does not need the information exchange between the primary side and the secondary side,and effectively reduces the difficulty of the system design.Based on the above theoretical analysis results,Built a system simulation model and experimental verification platform,and the simulation and experimental results verified the feasibility of the method proposed in this paper. |
